Prop-2-yn-1-ol

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Propargyl alcohol is not considered to cause toxicological relevant effects on fertility.

Link to relevant study records

Reference

Reference 1

Endpoint:

one-generation reproductive toxicity

Remarks:

based on test guideline

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

GLP guideline study (OECD 415) of a structural analogue. The target prop-2-yn-1-ol (propargyl alcohol; CAS no. 107-19-7) and its analogue chemical 2-butyne-1,4-diol (CAS no. 110-65-6) are considered read-across analogues based on structural similarity and similar physico-chemical and toxicological properties. The common structural features of the two substances are: a common functional methylol group; the methylol group(s) is/are bound to an alkyne structure; there are no elements other than carbon, hydrogen and oxygen; identical structures except for one additional methylol group on the alkyne structure of the source chemical 2-butyne-1,4-diol; similar molecular weights, both far below 500 daltons, qualifying as “low molecular weight” compounds. For a detailed read across justification see also attached assessment report.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

Deviations:

yes

Remarks:

The study was extended by examinations (estrous cycle, sperm parameters, organ weight determination in selected pups and parental animals, extended histology, signs of sexual maturation) that are required in the test guideline OECD 416.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Boehringer Ingelheim Pharma KG, Biberach/Riss, FRG
- Age at study initiation/Weight at study initiation/Acclimation period: The 112 male and 112 female rats were 28 (± 1) days old when they arrived from the breeding facilities. During an acclimatization period of 6 days, animals with lowest and highest body weights were eliminated. The 100 male and 100 female animals required for the study were 34 (± 1) days old at the beginning of treatment, and their mean weights and weight ranges were: male animals: 129.1 (103.8 - 149.2) g; female animals: 109.6 (96.5 - 123.2) g
- Housing: individually in type DK III stainless steel wire mesh cages supplied by BECKER & CO., Castrop-Rauxel, FRG with the following exceptions : from day 18 of gestation until day 14 after birth, the pregnant animals and their litters were also housed in Makrolon type M III cages supplied by BECKER & CO.
- Diet: Ground Kliba maintenance diet rat/ mouse / hamster, meal, supplied by KILINGENTALMUEHLE AG, Kaiseraugst, Switzerland, ad libitum.
- Water: Drinking water used to prepare aqueous BUTINDIOL solutions was of tap water quality. Water was supplied to the animals in the control group, and aqueous BUTINDIOL solutions were supplied to the animals in test groups (10; 80 and 500 ppm)*, using Makrolon drinking bottles supplied by BECKER & CO., Castrop-Rauxel, FRG, with a capacity of 300 mL. *)Drinking water was offered to the rats of the test groups during the acclimatization period.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): fully air-conditioned rooms
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES:
From: November 1998 To: April 1999 (F0 generation)
From: April/May 1999 To: April/May 1999 (F1 animals)

Route of administration:

oral: drinking water

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Drinking water solutions were prepared once or twice a week. The required weight of test substance was added to the appropriate amount of drinking water and agitated with a magnetic stirrer until the test substance was completely dissolved.

Details on mating procedure:

Matings of F0 generation parental animals:
In general, animals were mated overnight at a 1:1 or 1:2 ratio for a maximum of 2 weeks or until there was evidence of copulation. Generally, each male was mated with a predetermined female from the same dose group. Matings occurred by placing the female in the cage of a male from about 4.00 p.m. until 7.00 - 9.00 a.m. the following morning. A vaginal smear was prepared after each mating and examined for sperm. If sperm was detected, pairing of the animals was discontinued. The day on which sperm were detected was denoted "day 0" and the following day "day 1" p.c. (post coitum).

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical verification of the stability of the test substance in the drinking water for a period of 4 days at room temperature was carried out. The homogeneity of the test substance in the drinking water was guaranteed because Butindiol is completely soluble in water. Samples of each concentration were drawn for concentration control analyses at the start of the administration period for the F0 generation parental animals, after about 3 months and at the end of the study.

Duration of treatment / exposure:

F0: max. 20 weeks, F1: max. 8 weeks

Frequency of treatment:

continuous, once per day

Details on study schedule:

- Age at mating of the mated animals in the study: at least 76 days after treatment start, i.e. when the animals were about 110 days old (28 days old at delivery + 6 days acclimatization period + 76 days of treatment).

The F1 pups were raised up until day 21 post parturn (p.p.). Thereafter, the F1 weanlings with the exception of one male and one female pup/litter
and all FO adult animals were sacrificed. The selected F1 weanlings were reared until sexual maturation occurred and were killed thereafter .

Remarks:

Doses / Concentrations:
approx. 1 mg/kg body weight/day
Basis:
actual ingested
10 ppm nominal in water

Remarks:

Doses / Concentrations:
approx . 7.6 mg/kg body weight/day
Basis:
actual ingested
80 ppm nominal in water

Remarks:

Doses / Concentrations:
40 mg/kg body weight/day
Basis:
actual ingested
500 ppm nominal in water

No. of animals per sex per dose:

25 animals (F0)

Control animals:

yes, concurrent vehicle

Details on study design:

The study was extended by examinations (estrous cycle, sperm parameters, organ weight determination in selected pups and parental animals, extended histology, signs of sexual maturation) that are required in the following test guidelines :
• OECD Guideline for Testing of Chemicals, No . 416 (Sep. 1998)
• U.S. EPA, Health Effects Test Guidelines, OPPTS 870 .3800 Reproduction and Fertility Effects (Aug. 1998)


SELECTION OF DOSES/CONCENTRATIONS
The following concentrations in drinking water were selected:
10 ppm: as an expected "no observed adverse effect level"
80 ppm: as intermediate dose level
500 ppm: as highest dose level

Reason for species selection:
This strain was selected since extensive historical control data were available on Wistar rats and the rat is the preferred animal species for reproduction studies according to the different test guidelines.

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
At least once daily a check was made for dead or moribund animals . If animals were in a moribund state, they were sacrificed and necropsied .

DETAILED CLINICAL OBSERVATIONS: Yes
All parental animals were checked daily for clinical signs of toxicity . For technical reasons, however, the clinical observations recorded during the premating periods were printed out on a weekly basis. The nesting, littering, and lactation behavior of the dams was generally evaluated in the mornings in connection with the daily clinical inspection of the dams. The littering behavior of the dams was also inspected on weekdays (except holidays) in the afternoons in addition to the evaluations in the mornings. The day of littering was considered the 24 hour period from about 3 .00 p.m. of one day
until about 3.00 p.m. of the following day.

BODY WEIGHT: Yes
In general, the body weight of the FO parental animals was determined once a week in the morning. The body weight change was calculated from these results. The following exceptions are notable for the FO females: a) During each mating period females were weighed on the day of positive evidence of sperm (day 0 p.c.) and on days 7, 14 and 20 p.c. b) Females showing no positive evidence of sperm were not weighed during the mating interval. c) Females with litter were weighed on the day after parturition (day 1 p.p.) and on days 4, 7, 14 and 21 p.p. d) Females without litter were not weighed during the lactation phase.

FOOD CONSUMPTION: Yes
During the premating period of the F0 parental animals food consumption was determined once a week. After the 10th week food consumption of the females during pregnancy was determined for days 0-7, 7-14 and 14-20 p .c.. During the lactation period food consumption was determined for days 1-4,4-7, and 7-14 p.p.. Food consumption was not determined between days 14 and 21 after parturition, since during this time pups begin to consume considerable amounts of solid food offered, and therefore there was no point in such a measurement. Food consumption of the F0 males was not determined after the 10th test week through sacrifice. There was no determination of food consumption in the females during the mating periods, in the females without positive evidence of sperm during the programmed gestation phase, or, in the females without litters during the lactation phase.

WATER CONSUMPTION AND COMPOUND INTAKE: Yes
During the premating period of the FO parental animals water consumption was determined once a week. After the10th week, water consumption of the females during gestation was determined for days 0-1, 6-7, 13-14 and 19-20 p.c.. During the lactation period water consumption was determined for days 1-2,4-5, 7-8, 14-15 p.p.. Water consumption was not determined for days 20-21 after parturition, since during this time the pups will begin to consume considerable amounts of water and therefore there was no point in such a measurement. Water consumption of the FO males was not determined after the 10th study week until sacrifice. There was no determination of water consumption in the females during the mating periods, in the females without positive evidence of sperm during the programmed gestation phase, or, in the females without litters during the lactation phase.

The intake of test substance was calculated from the amount of drinking water consumed as follwos:
ITx = (WCx x D) / BWy
ITx=intake of test substance on day x in mg/kg body weight/day
WCx=daily water consumption on day x in grams
D=dose in ppm
BWy=body weight on day y in grams (last weighing before day x ).

Oestrous cyclicity (parental animals):

Estrous cycle length and normality were evaluated daily for all F0 female rats for a minimum of 3 weeks prior to mating and these evaluations were continued throughout the mating period until the female exhibited evidence of mating. At necropsy, a vaginal smear was examined to determine the stage of the estrous cycle for each F0 female with scheduled sacrifice.

Sperm parameters (parental animals):

After organ weight determination (necropsy) the right testis and cauda epididymis were taken from the F0 males of all dose groups. The following parameters were determined: sperm motility, sperm morphology, sperm head count (cauda epididymis), sperm head count (testis). Sperm morphology and sperm head count (cauda epididymis and testis) were evaluated for the control and highest dose group, only. The methods used are presented in "Any other information on materials and methods".

Litter observations:

STANARDISATION OF LITTERS:
- Performed on day 4 post partum: yes
Litters were standardized in such a way that each litter contained 4 male and 4 female pups (always the first 4 pups/sex and litter were taken for further rearing). If it was not possible in single litters to have 4 pups/sex, it was proceeded in such a way that 8 pups per litter were present for further rearing (e.g., 5 male and 3 female pups). Standardization of litters was not performed in litters with < 8 pups. Excess pups were killed and discarded.

PARAMETERS EXAMINED
Pup number and status at delivery:
All F1 pups were examined on the day of birth to determine the total number of pups and the number of live- and stillborn pups.

Pup viability/mortality:
In general, a check was made for any dead or moribund pups twice daily on workdays or as a rule, only in the morning on Saturdays, Sundays or public holidays. Dead pups were evaluated as described in "Postmortem examinations (Offspring)". The number and percentage of dead pups on the day of birth (day 0) and of pups dying between days 1-4, 5-7, 8-14 and 15-21 of the lactation period were determined; however, pups which died accidentally or had to be sacrificed due to maternal death were not included in these calculations. The number of live pups/litter was calculated on the day of birth, and on lactation days 4, 7, 14 and 21. Viability and lactation indices were calculated.

Sex ratio:
On the day of birth (day 0) the sex was determined by observing the distance between the anus and the base of the genital tubercle. The sex of the pups was finally confirmed at necropsy.
The sex ratio was calculated at day 0 and day 21 after birth according to the following formula:
Sex ratio = (number of live male or female pups on day 0/21 / number of live male and female pups on day 0/21) x 100

Pup body weight data:
The pups were weighed on the day after birth (day 1 p.p.) and on days 4 (before standardization), 7, 14 and 21 p.p.. Pups' body weight change was calculated from these results.

Pup clinical observations:
All live pups were examined once daily for clinical symptoms.

SELECTED F1 ANIMALS
Mortality: At least once daily a check was made for dead or moribund animals.

Clinical observations: All selected F1 animals were checked daily for clinical signs of toxicity.

Water consumption: Water consumption was determined once a week (each time for a period of 3 days).

Food consumption: Food consumption was determined once a week (each time for a period of 7 days).

Body weight data: Body weight was determined once a week in the morning. The body weight change was calculated from these results. Additionally, at the day of vaginal opening/preputial separation the body weights of the respective animals were also determined.

Sexual maturation data:
Vaginal opening: All female F1 pups selected to become the F1 animals (25/group) were evaluated daily for vaginal opening with examinations initiating on day 27 p.p. At the day of vaginal opening the body weights of the respective animals were additionally determined.
Preputial separation: All male F1 pups selected to become the F1 animals (25/group) were evaluated daily for preputial separation with examinations initiating on day 40 p.p . At the day of preputial separation the body weights of the respective animals were additionally determined.

Intake of test substance: The intake of test substance was calculated from the amount of drinking water consumed and expressed in mg/kg body weight per day . The calculation of the group values/day was carried out according to the following formula:
ITx = (WCx x D) / BWy
ITx=intake of test substance on day x in mg/kg body weight/day
WCx=daily water consumption on day x in grams
D=dose in ppm
BWy=body weight on day y in grams (last weighing before day x ).

Postmortem examinations (parental animals):

SACRIFICE / GROSS NECROPSY
The animals were sacrificed by decapitation under carbon dioxide anesthesia . The exsanguinated animals were necropsied and assessed by gross pathology.

ORGAN WEIGHTS
The following weight parameters of all F0 generation parental animals sacrificed at scheduled dates were determined:
1. anesthetized animals
2. liver
3. kidneys
4. epididymides (whole and cauda)
5. testes
6. uterus with oviducts and cervix uteri
7. ovaries
8. seminal vesicles (with coagulating glands and their fluids)
9. prostate gland
10. thymus
11. brain
12. pituitary gland
13. adrenal glands
14. spleen

HISTOPATHOLOGY
The following organs or tissues of all F0 generation parental animals were fixed in 4% formaldehyde or Bouin's solution, respectively :
1. all gross lesions
2. vagina
3. cervix uteri
4. uterus
5. ovaries (in Bouin's solution)
6. oviducts
7. left testicle (in Bouin's solution )
8. left epididymis (in Bouin's solution)
9. seminal vesicles
10. coagulating glands
11. prostate gland
12. pituitary gland
13. liver
14. kidneys
15. urinary bladder
16. thymus
17. spleen
18. brain
19. adrenal glands

After fixation, processing, the examination by light microscopy and the evaluation was performed according a table presented in "Any other information on materials and methods". An attempt was made to correlate the gross lesions with a meaningful microscopic finding.

Postmortem examinations (offspring):

Pup necropsy observations:
All pups with scheduled sacrifice were killed by means of carbon dioxide. These pups were examined externally and eviscerated, their organs were assessed macroscopically. In deviation to the protocol the pups of one F0 dam of the control group showing anasarca were not preserved and examined additionally since after evisceration no abnormal findings were noted.

Pup organ weights:
After scheduled sacrifice brain, spleen and thymus of 1 pup/sex and litter (selected per lot) from the F0-parents were weighed. For the calculation of the respective relative organ weights, the pup body weights determined routinely on day 21 p.p. were taken.

SELECTED F1 ANIMALS
All selected F1 animals were killed after sexual maturation was determined. These animals were examined externally and eviscerated, their organs were assessed macroscopically.

Statistics:

Statistics of the clinical examinations were performed and are presented in a table listed in "Any other information on materials and methods".

With respect to statistics of pathology, means and standard deviations of each test group were calculated for the variables of terminal body weight and of absolute and relative organ weights (related to terminal body weight) of the animals in each test group. Further statistics of pathology were performed and are presented in a table listed in "Any other information on materials and methods".

Reproductive indices:

Male reproduction data:
The mating partners, the number of mating days until vaginal sperm could be detected in the female, and the gestational status of the female were noted for F0 breeding pairs. For the males, mating and fertility indices were calculated for F1 litters according to the following formulas:

Male mating index (%) = (number of males with confirmed mating* / number of males placed with females) x 100
* defined by a female with vaginal sperm or that gave birth to a litter or with implantation sites/fetuses/pups in utero

Male fertility index (%) = (number of males proving their fertility* / number of males placed with females) x 100
*defined by a female giving birth to a litter or with implantation sites/fetuses/pups in utero

Female reproduction and delivery data:
The mating partners, the number of mating days until vaginal sperm could be detected, and gestational status were recorded for F0 females. For the females, mating, fertility and gestation indices were calculated for F1 litters according to the following formulas:

Female mating index (%) = (number of females mated * / number of females placed with males) x 100
*defined as the number of females with vaginal sperm or that gave birth to a litter or with implantation sites/fetuses/pups in utero

Female fertility index (%) = (number of females pregnant* / number of females mated**) x 100
* defined as the number of females that gave birth to a litter or with implantation sites/fetuses/pups in utero
** defined as the number of females with vaginal sperm or that gave birth to a litter or with implantation sites/fetuses/pups in utero

Gestation index (%) = (number of females with live pups on the day of birth / number of females pregnant*) x 100
*defined as the number of females that gave birth to a litter or with implantation sites/fetuses/pups in utero

Offspring viability indices:

Viability and lactation indices were calculated according to the following formulas:

Viability index (%) = (number of live pups on day 4* after birth / number of liveborn pups on the day of birth) x 100
*before standardization of litters (i .e. before culling)

Lactation index (%) = (number of live pups on day 21 after birth / number of live pups on day 4* after birth) x 100
*after standardization of litters (i .e. after culling)

With respect to the females, furthermore, the total number of pups delivered and the number of liveborn and stillborn pups were noted, and the live birth index was calculated for F1 litters according to the following formula:
Live birth index (%) = (number of liveborn pups at birth / total number of pups born) x 100

The implantations were counted and the postimplantation loss (in %) was calculated according the following formula:
Postimplantation loss (%) = (number of implantations - number of pups delivered / number of implantations) x 100

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
There were no substance-related mortalities in any of the F0 parental animals. No substance-related clinical sign nor any disturbance of thegeneral behaviour were detected in the F0 parental animals.

BODY WEIGHT (PARENTAL ANIMALS)
Mean body weights and mean body weight gains of all F0 parental males were not influenced by the test substance administration.
In the high dose group statistically significantly reduced mean body weights (BW) / body weight gains (BWC) in the females towards the end of premating (BWC about 10% reduced, if calculated for entire premating), during gestation (BWC without statistical significance) and lactation (BWC about 64 % reduced, if calculated for entire lactation)

DRINKING WATER AND FOOD CONSUMPTION (PARENTAL ANIMALS)
In the high dose group the following substance related findings were observed:
- statistically significantly reduced water consumption during premating (males: about 17% less, females: about 29% less, if calculated for entire premating), gestation (up to about 37% less) and lactation (up to about 24% less ).
- statistically significantly reduced food consumption of the F0 females during premating (up to 9% lower than the concurrent control), gestation (up to 6% lower than the concurrent control) and lactation (up to 10% lower than the concurrent control).
After administration of 7.6 mg/kg bw/d butindiol, statistically significantly reduced water consumption during premating (males: about 5% less, females: about 9% less, if calculated for entire premating) and gestation (up to about 18% less) were observed. No substance related adverse effects in males and females were found in the 1 mg/kg bw/d dose group.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
Mean test substance intake (mg/kg body weight/day)
F0 males 10 ppm: 0.9; 80 ppm: 7.6; 500 ppm: 39.5
F0 females (premating) 10 ppm: 1.1; 80 ppm: 8.0; 500 ppm: 40.5
F0 females (F1 litter) – gestation 10 ppm: 1.0; 80 ppm; 7.1; 500 ppm: 36.1
F0 females (F1 litter) – lactation 10 ppm: 1.6; 80 ppm: 12.7, 500 ppm: 69.6

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
No substance-related effect in all test groups.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
There occurred no treatment-related effects in the various sperm parameters examined at or after the sacrifice of the F0 parental males.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
Male reproduction data: There was no substance-related effect on the male mating or fertility index.

Female reproduction and delivery data:
The administration of Butindiol did not adversely affect reproduction and delivery data of the F0 generation parental females.

ORGAN WEIGHTS (PARENTAL ANIMALS)
In F0 females and males of the high dose groups
- statistically significantly increased mean absolute and relative kidney (males and females) and liver weights (females)
- statistically significantly decreased mean absolute and relative weights of the adrenal glands and thymus in females
were observed.
In the mid dose groups
- statistically significantly increased mean absolute (males) and relative kidney weights (males and females)
- statistically significantly increased mean absolute and relative liver weights in females
were found
In the low dose groups there were no substance-related effects.

GROSS PATHOLOGY (PARENTAL ANIMALS)
The majority of the few gross lesions noted occurred singly in control and/or low, mid or high dose groups, with no indication of a relationship to treatment.

HISTOPATHOLOGY (PARENTAL ANIMALS)
Histopathology did not reveal treatment related microscopic findings in any of the organs of F0 males and females.

Dose descriptor:

NOAEL

Remarks:

general, systemic toxicity

Effect level:

ca. 1 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Reduced water consumption, increased kidney and liver weights at 7.6 mg/kg bw/day

Dose descriptor:

NOAEL

Remarks:

reproductive performance, fertility

Effect level:

ca. 40 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No adverse effects at high dose

VIABILITY (OFFSPRING)
Pup number and status at delivery: The mean number of delivered F1 pups/dam and the rate of liveborn and stillborn pups were not affected by the administration of the test substance.

Pup viability/mortality: The viability indices as indicators for perinatal pup mortality were 90% / 91% / 91 % and 94% in the respective groups(0, 10, 80 and 500 ppm). The lactation indices as indicators for pup mortality between days 4-21 p.p. reached 97% / 99% / 99% and 100%.Thus, there were no substance-related differences between the control and the 10, 80 and 500 ppm F1 pups concerning viability and mortality.

Sex ratio: The sex distribution and sex ratios of live F1 pups on the day of birth and on day 21 p.p. did not show any substantial differences between controls and treated groups.

CLINICAL SIGNS (OFFSPRING)
The F1 generation pups did not show any clinical signs up to weaning which could be attributed to the treatment.

BODY WEIGHT (OFFSPRING)
In the high dose group statistically significantly lower mean body weights in F1 pups from day 14 p.p. until weaning (about 14% on day 21 p.p., both sexes combined) and statistically significantly impaired body weight gains in these pups from day 7 p.p. up to weaning (if calculated for days 4 - 21 p .p.about 18%, both sexes combined) were found, whereas no substance related adverse effects were observed in the middle and low dose groups.

ORGAN WEIGHTS (OFFSPRING)
Absolute pup organ weights:
Mean brain, thymus and spleen weights of F1 pups (both sexes combined) were statistically significantly reduced in the high dose group. However, the lower absolute pup organ weights at high dose were considered to be a result of the significant decrease in mean pup body weights at this dose level. There were no substance related adverse effects at mid or low dose.

Relative pup organ weights:
The mean brain weights of F1 pups (both sexes combined) were statistically significantly increased in the high dose group, while the mean thymus weights in the same test group were statistically significantly reduced. This was assessed as a consequence of the significant decrease in mean pup body weights at this dose level. There were no substance related adverse effects at mid or low dose.

GROSS PATHOLOGY (OFFSPRING)
Pup necropsy observations:
The macroscopic examination of stillborn pups, pups that died intercurrently, culled and surplus pups of F1 litters did not reveal any
substance related findings.

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FINDINGS IN SELECTED F1 ANIMALS (REARED F1 WEANLINGS)
------------------------------------------------------------------------------------

The examinations reported below covered the period until sexual maturation (=end of study), i.e. a period of three to four weeks after weaning.

CLINICAL OBSERVATIONS/ MORTALITY
There were neither mortalities nor clinical observations.

WATER CONSUMPTION/ FOOD CONSUMPTION/ BODY WEIGHT
In the high dose group
- statistically significantly reduced water consumption during the treatment period (weeks 0 - 3 in females and weeks 0 - 4 in males), if calculated for the entire period about 22% lower in both sexes in comparison to control
- statistically significantly reduced food consumption of the males (about 10% below control, if calculated for the whole period)
- statistically significantly reduced mean body weights (BW) / body weight gains (BWC) in the males (BWC about 9% reduced, if calculated for the entire period)
- reduced mean body weights of up to 11 % in the females attaining statistical significance during weeks 0 and 1 were observed. There were no substance related adverse effects at mid or low dose.

SEXUAL MATURATION DATA
Vaginal opening:
Each selected F1 female animal (reared F1 weanling) was evaluated for vaginal opening. The first and the last day, when vaginal opening occurred were day 27 or 42 p.p., respectively. The mean age for vaginal opening was slightly but statistically significantly delayed in the high dose group (33.6 days in contrast to 31.1, 31.5 and 30.8 for the 0, 10 and 80 ppm groups, respectively). However, this observation was not assessed as a direct, substance specific delay of sexual maturation since the body weights/body weight gains in the phase until weaning were affected and moreover, the body weights were statistically significantly reduced in the observation period after weaning. Consequently, the recognized effect was assessed to be a result of a general retardation of development.

Preputial separation:
Each selected F1 male animal (reared F1 weanling) was evaluated for preputial separation. The first and the last day, when preputial separation occurred were day 42 or 53 p.p., respectively. The mean age for preputial separation was slightly but statistically significantly delayed in the high dose group (46.2 days in contrast to 44.6, 44.9 and 45.6 for the 0, 10 and 80 ppm groups, respectively). However, this observation was not assessed as a direct, substance specific delay of sexual maturation since the body weights/body weight gains in the phase until weaning were affected and moreover, the body weights were statistically significantly reduced in the observation period after weaning. Consequently, the recognized effect was assessed to be a result of a general retardation of development.

INTAKE OF TEST SUBSTANCE
Overall approx. values for mean test substance intake (mg/kg body weight/day) are presented below (test group, value):
Selected F1 males: 10 ppm, 1.6; 80 ppm, 12.4; 500 ppm, 71.6
Selected F1 females: 10 ppm, 1.8; 80 ppm, 13.7; 500 ppm, 76.9

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Generation:

F1

Effect level:

ca. 7.6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Pup body weight reduction and related organ weight changes, delayed preputial separation/vaginal opening at high dose

Reproductive effects observed:

no

Executive summary:

In an extended one-generation reproduction study Butindiol (99.5 % a.i.) was administered to 25 male and 25 female rats in drinking water at nominal dose levels of 0, 10, 80 or 500 ppm (approximately 0, 1.0, 7.6 or 40 mg/kg bw/day, respectively). At least 76 days after the beginning of treatment, F0 animals were mated to produce a litter (P). The F1 pups were raised up until day 21 post partum (p.p.). Thereafter, the F1 weanlings with the exception of one male and one female pup/litter and all F0 adult animals were sacrificed. The selected F1 weanlings were reared until

sexual maturation occurred and were killed thereafter. Drinking water containing Butindiol was administered continuously throughout the study .

There were no indications from the clinical and pathological examinations, that the administration of Butindiol had adverse effects on reproductive performance or fertility of the F0 parental animals of all substance-treated groups. Estrous cycle data, mating behavior, conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights, gross and histopathological findings of these organs revealed no substance-related adverse effects. Most of the F0 parental rats proved to be fertile. The scattered occurrence of individual infertile rats throughout the different dose groups did not suggest any relation to treatment. Signs of general, systemic toxicity in the F0 parental generation were confined to the rats of the 80 and 500 ppm groups. Reduced water consumption during premating in the F0 parental rats as well as during gestation and lactation in the F0 females were observed at 500 ppm. Impairments in body weight/body weight gain were noted for the F0 females during premating, gestation and lactation with concurrent lowered food consumption. Concerning pathology, substance-induced statistically significantly increased absolute and relative kidney weights (both F0 sexes) and liver weights (F0 females) as well as statistically significantly decreased absolute and relative weights of the adrenal glands and thymus in F0 females occurred at 500 ppm. At 80 ppm impaired water consumption was noted during premating (both F0 sexes) and gestation (F0 females), while pathology revealed statistically significantly increased absolute and relative kidney (both F0 sexes) and liver weights (F0 females). Moreover, the examinations of the selected F1 animals performed until sexual maturation indicated signs of general systemic toxicity at 500 ppm in form of reduced water consumption (both sexes), impaired body weight/body weight gain in the selected F1 males with concurrent reductions in food consumption as well as reduced body weights in the selected F1 females. Substance-induced signs of developmental toxicity were observed in progeny of the F0 parents at 500 ppm. The administration led to impairments of pup body weight data and causally related pup organ weight changes occurred in the high dose progeny of the F0 parental rats. Furthermore, a delay in preputial separation/vaginal opening in the selected F1 males/females was noted as a sign of a general delay in physical development. Dose levels of 10 or 80 ppm did not induce any indications of developmental toxicity. Therefore, under the conditions of this study the NOAEL (no observed adverse effect level) for reproductive performance and fertility is 500 ppm (about 40 mg/kg bw/day) for the F0 parental rats.The NOAEL for general, systemic toxicity of the test substance is 10 ppm (about 1 mg/kg bw/day) for the F0 parental males and females. The NOAEL for developmental toxicity (growth and development of the offspring) could be fixed at 80 ppm (about 7.6 mg/kg bw/day) for the F1 progeny. Thus, indications for developmental toxicity occurred only at a dose, which was also toxic to the parental animals.

This extended study is acceptable and satisfies the guideline requirement for a one-generation reproductive study (OECD 415) in rats.

Reference 2

Endpoint:

toxicity to reproduction

Remarks:

other: subchronic toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study is scientifically valid and followed the principles of OPPTS Test Guideline 870.8700 for subchronic oral toxicity.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA OPPTS 870.8700 (Subchronic Oral Toxicity Test)

Deviations:

not applicable

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

no details available

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Test Item was given as aqueous solution.

Details on mating procedure:

not applicable

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
0, 5, 15 or 50 mg/kg bw/day
Basis:
nominal in water

No. of animals per sex per dose:

20 rats/sex/dose and control group

Control animals:

yes

Details on study design:

- 40 Animals (20/sex/dose group) were used
- Interim sacrifice of animals was peformed (10/sex/dose group)
- Recovery group was not included

Positive control:

no

Parental animals: Observations and examinations:

Rats were sacrificed on days 91 or 92 after dosing.
Gross pathology and histopathology was performed.

CLINICAL SIGNS AND MORTALITY:
Treatment-related mortality was reported in the 50 mg/kg dosage group, although the precise cause was not identified.
4 male rats of the 50 mg/kg dose group died. Animals belonging to this dose group showed marked salivation.

BODY WEIGHT AND WEIGHT GAIN:
The body weight of males of the highest dose group were significantly lower compared to the control group. In case of the females there was only a tendency towards lower body weights compared to the controls.

OPHTHALMOSCOPIC EXAMINATION:
The ophtalmological examination was without findings.

HAEMATOLOGY:
No changes in haematological parameters were reported in the rats of the 5 mg/kg dose group. In males of the highest dose group reduced values for haemoglobin, mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were measured. In females of the highest dose group only reduced values for MCH and MCHC were observed. Neutrophil counts were significantly increased in males of the mid- and high-dose group (15 and 50 mg/kg bw/day). Hematological changes were seen in the mid- and high-dose animals and were considered to be treatment- related.

CLINICAL CHEMISTRY:
No changes in clinical pathology parameters were reported in the rats of the 5 mg/kg dosage group.
Enzyme changes characteristic of liver damage were seen in the mid- and high-dose animals. These changes included significantly increased ALAT, ASAT, LDH, and ALP serum activities. Moreover, decreased glucose, sodium, total cholesterol, total protein, albumin, globulin, and creatinine serum levels were seen, whereas inorganic phosphate and total bilirubin serum levels were significantly higher.

ORGAN WEIGHTS:
Treatment-related effects at the 15 mg/kg/day dose level included increased liver weights in both genders, increased kidney weights in females, and megalocytosis of the liver after 13 weeks of dosing.

GROSS PATHOLOGY
Macroscopic findings were confined to the liver (15 and 50 mg/kg bw) and the stomach (50 mg/kg bw).

HISTOPATHOLOGY: NON-NEOPLASTIC
Hepatocytic megalocytosis with a less prominent proliferation of the bile ducts and cytoplasmic vacuolation of hepatocytes was observed in all rats in the 50 mg/kg group dosed for 3 months, in all 15 mg/kg rats dosed for 3 months. In the low-dose group, megalocytosis was seen only in one rat treated for 3 months. Karyomegaly of renal tubular epithelial cells was reported to occur in a dose-response fashion in the mid- and high-dose groups, but not in the low-dosage group.

Dose descriptor:

NOAEL

Effect level:

5 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: effects on clinical chemistry, organ weight, histopathology at higher dose levels

Reproductive effects observed:

not specified

Executive summary:

Male and female Crl:CD(SD)BR rats (n=20/sex/group) were dosed orally (gavage) with 0, 5, 15 or 50 mg/kg bw of Propargyl alcohol (purity: >99%) (at 10 mL/kg in deionised water) daily for 13 weeks. Rats were sacrificed on days 91 or 92 after dosing. Parameters examined included clinical signs, body and organ weight changes, food consumption, ophthalmology, haematology, blood chemistry and histological evaluations. Treatment-related mortality was reported for 4/30 males in the high-dose group. The most prevalent clinical sign was salivation, occurring mainly at 50 mg/kg bw. Body weights were significantly lower in the high-dose animals. Haematological changes observed in the high-dose animals comprised decreased haemoglobin, MCV (also at 15 mg/kg bw), MCH, and mean corpuscular haemoglobin concentration (MCHC) values. Enzyme changes characteristic of liver damage were seen in the mid- and high-dose animals. These changes included significantly increased ALAT, ASAT, LDH, and ALP serum activities. Moreover, decreased glucose, sodium, total cholesterol, total protein, albumin, globulin, and creatinine serum levels were seen, whereas inorganic phosphate and total bilirubin serum levels were significantly higher. The haematological and blood chemistry changes were considered to be treatment-related. Absolute and relative liver and kidney weights were significantly increased in males and/or females at 15 and 50 mg/kg bw/day. At 5 mg/kg bw, mean absolute and relative liver weights were higher compared to controls, but statistical significance was not reached. Macroscopic findings were confined to the liver (15 and 50 mg/kg bw) and the stomach (50 mg/kg bw). Hepatocytic megalocytosis with a less prominent proliferation of the bile ducts and cytoplasmic vacuolation of hepatocytes was observed in the majority of rats in the mid- and high-dose groups. In the low-dose group, megalocytosis was seen only in one rat treated for 3 months. Karyomegaly of renal tubular epithelial cells was reported to occur in a dose-response fashion in the mid- and high-dose groups, but not in the low-dose group. Treatment-related effects at 15 mg/kg bw included increased liver weights in both genders, increased kidney weights in females, and megalocytosis of the liver after 13 weeks of dosing. The daily oral administration of 5 mg/kg bw/day of propynol produced no apparent treatment-related effects and hence this dose level was considered a NOAEL for subchronic oral exposure to Propargyl alcohol.

Reference 3

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2004-11-23 to 2005-01-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3550 (Reproduction/Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Wistar rats Crl:WI(Han) (former: CrlGIxBrIHan:WI)
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH (former name: Charles River Laboratories, Germany)
- Age at study initiation: (P) Males: 10-11 wks; Females: 9-10 wks
- Weight at study initiation: (P) Males: 311.9-315.2 g; Females: 194.6- 197.1 g
- Housing: The rats were housed individually in type DK III stainless steel wire mesh cages supplied by Becker & Co., Castrop-Rauxel, Germany (floor area of about 800 cm²), with the following exceptions:
* ovemight matings: male and female mating partners housed together in type DK III cages
* gestation day 18 - Iactation day 21: pregnant animals and their litters housed in Makrolon type M III cages.
The M III cages were also supplied by Becker & Co.. Pregnant females were provided with nesting material (cellulose wadding) toward the end of gestation. The cages with the test animals were arranged on the racks in such way that uniform experimental conditions (ventilation and Iight) were ensured.
- Diet: The food used was ground Kliba maintenance diet mouse/rat "GLP" meal, supplied by Provimi Kliba SA, Kaiseraugst, Switzerland, which was available to the animais ad libitum throughout the study (from the day of supply to the day of or the day before necropsy).
- Water: Drinking water was supplied from water bottles (ad libitum).
- Acclimation period: 1 week (November 23, 2004 - December 01, 2004)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24°C
- Humidity (%): 30 - 70%
- Air changes (per hr): air-conditioned rooms
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 2004-11-23 To: 25-01-2005

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
For the preparation of the solutions, the test substance was weighed in a graduated measuring flask depending on the dose group, topped up with doubly distilled water. The test substance solutions were prepared at the beginning of the administration period and thereafter twice weekly.

VEHICLE
- doubly distilled water
- Concentration in vehicle: 0, 0.05, 0.15 or 0.45 g/100 mL
- Amount of vehicle: 10 mL/kg bw

Details on mating procedure:

- M/F ratio per cage: 1:1 (paired overnight)
- Length of cohabitation: max. 14 days
- Proof of pregnancy: If sperm was detected, pairing of the animals was discontinued. The day on which sperm were detected was denoted "day 0" and the following day "day 1" post coitum.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

All analyses of the test substance preparations were carried out at the Analytical Chemistry Laboratory of the Experimental Toxicology and Ecology of BASF Aktiengesellschaft, Ludwigshafen, Germany.
Due to the high solubility of the test substance in water, no homogeneity analyses were performed.
Concentration control analyses were performed with samples drawn from all doses at the start and at the end of the administration period.
The concentration control analyses of the aqueous test substance solutions revealed that the values were in the expected range of the target concentrations (Mean values: 99.5% and 106.0%). Thus, the correctness of the prepared concentrations was conflrmed.

Duration of treatment / exposure:

F0 male: 2004-12-02 to 2005-01-02
F0 female: 2004-12-02 to 2005-01-24

The test substance was administered orally via gavage to the F0 animals once a day approximately the same time of day (in the morning). The treatment lasted up to one day prior to sacrifice. The animals of the control group were treated in the same way with the vehicle only (doubly distilled water). The volume administered each day was 10 mL/kg bw. The calculation of the volume administered was based on the most recent individual body weight.
At least 14 days after the beginning of treatment, males and females from the same dose group were mated overnight in a ratio of 1:1.
After 32 days of the treatment beginning, the male animals were sacrificed under carbon dioxide anesthesia.
The females were allowed to litter and rear their pups until day 4 after parturition. On study day 54 the F0 parental female animals were sacrificed under carbon dioxide anesthesia.

Frequency of treatment:

once daily

Details on study schedule:

- Age at mating of the mated animals in the study: 86 ± 2 days old (males), 79 ± 2 days old (females)

Remarks:

Doses / Concentrations:
0, 5, 15, 45 mg/kg bw/d
Basis:
nominal in water

No. of animals per sex per dose:

F0 generation: 10 animals

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: selection was performed based on a request by the Sponsor

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Mortality - A check was made twice daily on working days and once daily on Saturdays, Sundays and public holidays.
- Time schedule: All parental animals were checked daily for clinically evident signs of toxicity.

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations:
In general, the body weight of the male and female parental animals was determined once a week at the same time of the day (in the morning). The difference between the body weight on the respective day of weighing and the body weight on study day 0 was calculated as body weight change.
The following exceptions are notable for the female animals:
- During the mating period the parental females were weighed on the day of positive evicience of sperm (day 0 post coitum) and on days 7, 14 and 20 post coitum.
- Females without positive evidence of sperm were weighed weekly. These body weight data were solely used for the calculations of the dose volume.
- Females with litter were weighed on the day of parturition (day 0 post partum) and on day 4 postpartum.
- Females without litter were weighed weekly. These body weight data were solely used for the calculation of the dose volume.

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Generally, food consumption was determined once a week (in general for a period of 7 days) for male and female animals.
The following exceptions were notable:
- Food consumption was not determined during the mating period (male and female F0 animals).
- Food consumption of the F0 females with evidence of sperm was determined on days 0, 7, 14 and 20 post coitum.
- Food consumption of F0 females, which gave birth to a litter was determined on days 0 and 4 post partum.

Litter observations:

PUP CLINICAL OBSERVATIONS:
In general, a check was made for any dead or moribung pups twice daily on workdays (once in the morning and once in the afternoon) or as a rule, only in the morning on Saturdays, Sundays or public holidays. The live pups were examined each day for clinical symptoms (including gross-morphological findings).

PUP BODY WEIGHT DATA:
The pups were weighed one day after birth (day 1 post partum) and on day 4 after birth.
Pups' body weight change was calculated from these results.
Furthermore the body weights on day 1 post partum were used for the calcutation of "runts" (pups, which weighed more than 25% less than the mean weight of the respective control pups).
The individual weights were always determined at about the same time of the day (in the morning).

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; a macroscopical examination was performed on all pups that died prematurely.

Postmortem examinations (parental animals):

PATHOLOGY

Necropsy:
The animals were sacrificed by decapitation under carbon dioxide anesthesia. The exsanguinated animals were necropsied and assessed by gross pathology. Animals which died intercurrently were necropsied as soon as possible after their death and assessed by gross pathology.

Organ weights:
The following weight parameters from all animals sacrificed at scheduled dates were determined:
1. anesthetized animals
2. testes
3. epididymides
4. ovaries

Organ / Tissue fixation:
The following organs or tissues were fixed:
1. all gross lesions
2. pituitary gland
3. prostate gland, seminal vesicles, coagulation glands
4. uterus*, oviducts, cervix uteri, vagina

Histopathology:
Light microscopical examination was performed as listed (Organs (Test groups)):
Testes (0, 2) - hematoxylin and eosin stain, all animals per group
Epididymides (0, 2) - hematoxylin and eosin stain, all animals per group
Ovaries (0, 2) - hematoxylin and eosin stain, all animals per group
All gross lesions (0, 1, 2) - hematoxylin and eosin stain, all animals affected per group

Postmortem examinations (offspring):

PUP NECROPSY OBSERVATIONS:
All surviving pups (after sacrifice on day 4 p.p.), all stillborn pups and those pups that died before schedule, were examined externally, eviscerated and their organs were assessed macroscopically.

Statistics:

Statistics of the clinical examinations:
Please refer to "Any other information on materials and methods incl. tables".

Statistics of pathology
Means and standard deviations were calculated. In addition, statistical analyses were carried out. Please refer to "Any other information on materials and methods incl. tables".

Reproductive indices:

Male reproduction data:
The pairing partners, the number of mating days until vaginal sperm could be detected in female animals, and the gestational status of the female were noted for F0 breeding pairs. For the males, mating and fertility indices were calculated according to the following formulas:

Male mating index (%) = (number of males with confirmed mating*/number of males placed with females) x 100
* defined by a female with vaginal sperm or that gave birth to a litter or with pups/implantations in uterus

Male fertility index (%) = (number of males proving their fertility*/number of males placed with females) x 100
* defined by a female giving birth to a litter or with pups/implantations in uterus

Female reproduction data:
The pairing partners, the number of mating days until vaginal sperm could be detected, and gestational status were recorded.
For the females, mating, fertility and gestation indices were calculated according to the following formulas:

Female mating index (%) = (number of females mated* / number of females placed with males) x 100
* defined as the number of females with vaginal sperm or that gave birth to a litter or with pups/implantations in uterus

Female fertility index (%) = (number of femals pregnant*/ number of females mated**) x 100
* defined as the number of females with vaginal sperm or that gave birth to a litter or with pups/implantations in uterus
** deflned as the number of females with vaginal sperm or that gave birth to a litter or with pups/implantations in uterus

Gestation index (%) = (number of females with live pups on the day of birth/ number of females pregnant*) x 100
* defined as the number of females that gave birth to a litter or with pups/implantations in uterus

Offspring viability indices:

Delivery data:
The total number of pups delivered and the number of liveborn and stillborn pups were noted and the live birth index was calculated according to the following formula:

Live birth index (%) = (number of liveborn pups at birth/total number of pups born) x 100

Moreover, after sacrifice of the female animals, the implantation sites were counted and the postimplantation loss was calculated for each individual pregnant animal according to the following formula:

Post implantation loss (%) = ([number of implanatations - number of pups delivered]/number of implantations) x 100


Pup viability/mortality:

In general, a check was made for any dead or moribund pups twice daily on workdays (once in the morning and once in the afternoon) or as 5 rule, only in the morning on Saturdays, Sundays or public holidays. Dead pups were evaluated.

The number and percentage of dead pups on the day of birth (day 0) and of pups dying between days 1-4 of the lactation period were determined; however, pups which died accidentally and pups which were sacrificed due to maternal death were not included in these calculations. The number of live pups/litter was calculated on the day of birth, and on lactation day 4.

Furthermore the viability index was calculated according to the following formula:

Viability index (%) = (number of live pups on day 4 after birth/number of live pups on the day of birth) x 100


Sex ratio:
On the day of birth (day 0) the sex of the pups was determined by observing the distance between the anus and the base of the genital tubercle; normally, the anogenital distance is considerably greater in male than in female pups. The sex of the pups finally confirmed at necropsy.

The sex ratio was calculated at day 0 and day 4 after birth according to the following formula:

Sex ratio = (number of live male or female pups on day 0/4 / number of live male and female pups on day 0/4) x 100

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)

Two males and one female from the high dose group were found dead on the first week of study. Due to mortality and a significant reduction observed in food intake and body weight values, the treatment of this dose group was discontinued. The animals were sacrificed prematurely and assessed by gross pathology.

One male and two females from the high dose group showed an impairment of their clinical state during the first week of treatment. The male and one female were found dead during the same study week. No substance related clinical findings were observed in any other dose group. There were no particular substance-related clinical findings in any F0 females during the gestation period. No substance-related clinical findings were reported during the lactation period.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)

Body weights of males from the high dose group were observed slightly but significantly reduced during the first week ot treatment (-5 %). During the same week of treatment (0-1), high dose males and females gained statistically significantly less weight than controls. Body weight and body weight gain during gestation and Iactation periods were not affected, with the exception of body weight gain in females from the low dose group during lactation, which was found slightly but significantly increased. This finding has no biological relevance and was not considered related to the treatment.

The food consumption of the high dose groups was statistically significantly reduced during the first study week for both sexes (-19 % males and -20 % females). During lactation, food consumption was slightly but significantly increased in low dose females. This marginal increase was considered not biologically relevant and not related to treatment.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)

Male reproduction data:

For all F0 parental males of low and mid dose groups mating was confirmed. The male mating index reached 100 % in all groups including controls. For most of the parental males fertility was confirmed within the scheduled mating intervals for F1 litter. The male fertlllty index was 100 % for the control and low dose groups, and 90 % for the mid dose group. A substance-induced effect on male fertility was excluded, as only a single pair appeared to be infertile. Gross and histopathological examinations of this male failed to show a relevant morphological correlation.

Female reproduction and delivery data:

The female mating index was 100 % in low and mid dose groups and controls. The mean cohabitation times were 3.9 days in controls, 2.4 days at low and 2.7 days at mid dose. These differences between the groups are assessed as being spontaneous and without any biological relevance. Therefore, the female fertility index was 100 % for the control and low dose groups, and 90 % for the mid dose group. A substance-induced effect on female fertility was excluded, as only a single pair appeared to be infertile. Gross pathology and histopathological examinations of this female failed to show a relevant morphological correlation. The mean duration of gestation was similar in all test groups (between 21.9 and 22.1 days).

The gestation index was 100 % in all groups of females.

The mean number of implantation sites per dam was found slightly but statistically significantly increased at low dose (13.4 implantations against 11.5 in the control group). This marginal increase was considered as being spontaneous and not treatment related. No significant differences in post implantation loss were observed (6.8, 7.6 and 4.2 % in the control, low and mid dose groups, respectively). The mean number of F1 pups delivered/dam was not affected at the low or mid dose. Live- and stillborn pups were comparable between the groups. The live birth index varied between 99 and 100 %.

ORGAN WEIGHTS (PARENTAL ANIMALS)
There were no significant organ weight changes noted.

GROSS PATHOLOGY (PARENTAL ANIMALS)
All gross lesions noted were regarded to be spontaneous and not treatment related.


HISTOPATHOLOGY (PARENTAL ANIMALS)
There were no treatment-related microscopic findings.

Dose descriptor:

NOAEL

Effect level:

15 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: general, systemic toxicity, reproductive performance, fertility

LITTER DATA (OFFSPRING)
All F0 pregnant females were able to litter their pups. The numbers of live- and stillborn pups were similar at low and mid dose as compared to controls. The mean number of delivered F1 pups/dam and the percentage of liveborn pups were not affected at low and mid dose. The marginal differences observed were without biological relevance and dose-response relationship.

VIABILITY/MORTALITY (OFFSPRING)
One stillborn pup was reported in the control group and one pup from the F0 low dose group was cannibalized. No significant viability index as an indicator for pup mortality was observed. The sex distribution and sex ratios of live F1 pups on the day of birth and 4 days post partum did not show any substantial differences between control and test groups.

CLINICAL SIGNS (OFFSPRING)
No additional abnormalities were note in the test groups.

BODY WEIGHT (OFFSPRING)
Pup body weights and pup body weight gains were not affected by treatment at low or mid dose.

GROSS PATHOLOGY (OFFSPRING)
All examined pups were without macroscopic findings.

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

15 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: developmental toxicity / F1 progeny

Reproductive effects observed:

not specified

Executive summary:

In a reproduction/developmental toxicity screening study Propargyl Alcohol (99 % a.i.) was administered orally via gavage to groups of 10 male and 10 female Wistar rats (F0 animals) at dose levels of 5, 15 or 45 mg/kg bw/day in order to observe possible effects on the integrity and performance of the reproductive system of both sexes (males: 32 days until sacrifice, females: 54 days until sacrifice). Control animals were dosed daily with the vehicle (doubly distilled water).
Three animals (2 males and 1 female) from the high dose group died during the first week of treatment. Before their death, these animals and one additional high dose female showed an impairment of their general state of health. A significant reduction of food consumption and body weight gains were also reported in animals of the high dose group. After one week, the treatment was discontinued and the high dose group animals were sacrificed and assessed by gross pathology. No substance-related findings were observed during gross pathology.

No signs of general, systemic toxicity and no adverse effects on fertility and reproductive performance were noted in the F0 parental animals of both sexes of the 5 and 15 mg/kg bw/day groups. No signs of developmental toxicity were observed in the F1 pups of the 5 and 15 mg/kg bw/day groups. Thus, under the conditions of this study, the NOAEL for general, systemic toxicity, reproductive performance and fertility of the F0 parental rats and the NOAEL for developmental toxicity in the F1 progeny was 15 mg/kg bw/day. At 45 mg/kg bw/day marked toxicity and lethality was noted. These findings justify the premature termination of this dose group, since they precluded a meaningful assessment of fertility and reproduction in these animals.

This reproduction/developmental screening test in the rat is classified as acceptable and satisfies the guideline requirement (OECD 421).

Reference 4

Endpoint:

extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

Justification for data waiving

An extended one-generation reproductive toxicity study is considered scientifically not necessary according to REACh Regulation, annex XI, section 1.2 for the following reasons:
The effects of 2-propyn-1-ol (propargyl alcohol) on fertility of parental animals and development of their offspring were determined in an OECD 421 screening study, in which groups of ten male and ten female rats were treated orally via gavage at dose levels of 0, 5, 15, and 45 mg/kg bw in order to observe possible effects on the integrity and performance of the reproductive system of both sexes. Three animals (two males and one female) from the high-dose group died during the first week of treatment. Before their death, these animals and one additional high-dose female showed an impairment of their general state of health. A significant reduction of food consumption and body weight gains were also reported in animals of the high-dose group. After one week, the treatment was discontinued and the high-dose group animals were sacrificed and assessed by gross pathology. The premature death of the high-dose animals might be explained by acute toxic effects mediated by propargyl alcohols’ general toxicity (LD50 = 56.4 mg/kg bw vs. 45 mg/kg bw administered to high-dose animals). No substance-related findings were observed during gross pathology. No signs of general, systemic toxicity and no adverse effects on fertility and reproductive performance were noted in the F0 parental animals of both sexes of the 5 and 15 mg/kg bw/day groups. No signs of developmental toxicity were observed in the F1 pups of the 5 and 15 mg/kg bw/day groups. Therefore, the NOAEL for general, systemic toxicity, reproductive performance, fertility of the F0 parental rats and the NOAEL for developmental toxicity in the F1 progeny was 15 mg/kg bw/day. At 45 mg/kg bw/day marked toxicity and lethality was noted. These findings justify the premature termination of this dose group, since they precluded a meaningful assessment of fertility and reproduction in these animals (see also respective RSS).
Furthermore, an one-generation reproduction toxicity study (OECD 415) conducted with the read-across substance 2-butyne-1,4-diol (CAS 110-65-6) showed that fertility was not disturbed at any stage. Briefly, 2-butyne-1,4-diol was administered to 25 male and 25 female rats in drinking water at nominal dose levels of 0, 10, 80, or 500 ppm (approximately 0, 1.0, 7.6, or 40 mg/kg bw). At least 76 days after the beginning of treatment, F0 animals were mated to produce a litter (P). The F1 pups were raised up until day 21 post-partum (p.p.). Thereafter, the F1 weanlings with the exception of one male and one female pup/litter and all F0 adult animals were sacrificed. The selected F1 weanlings were reared until sexual maturation occurred and were killed thereafter. Drinking water containing 2-butyne-1,4-diol was administered continuously throughout the study. There were no indications from the clinical and pathological examinations, that the administration of 2-butyne-1,4-diol had adverse effects on reproductive performance or fertility of the F0 parental animals of all substance-treated groups. Estrous cycle data, mating behavior, conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights, gross and histopathological findings of these organs revealed no substance-related adverse effects. Most of the F0 parental rats proved to be fertile. The scattered occurrence of individual infertile rats throughout the different dose groups did not suggest any relation to treatment. Signs of general, systemic toxicity in the F0 parental generation were confined to the rats of the 80 and 500 ppm groups. However, there were no substance-related mortalities in any of the F0 parental animals. This might be explained by changed absorption kinetics of 2-butyne-1,4-diol as a result of drinking water administration as compared with a bolus administration of propargyl alcohol in the above mentioned screening study. Reduced water consumption during premating in the F0 parental rats as well as during gestation and lactation in the F0 females were observed at 500 ppm. Impairments in body weight/body weight gain were noted for the F0 females during premating, gestation and lactation with concurrent lowered food consumption. Concerning pathology, substance-induced statistically significantly increased absolute and relative kidney weights (both F0 sexes) and liver weights (F0 females) as well as statistically significantly decreased absolute and relative weights of the adrenal glands and thymus in F0 females occurred at 500 ppm. At 80 ppm impaired water consumption was noted during premating (both F0 sexes) and gestation (F0 females), while pathology revealed statistically significantly increased absolute and relative kidney (both F0 sexes) and liver weights (F0 females). Moreover, the examinations of the selected F1 animals performed until sexual maturation indicated signs of general systemic toxicity at 500 ppm in form of reduced water consumption (both sexes), impaired body weight/body weight gain in the selected F1 males with concurrent reductions in food consumption as well as reduced body weights in the selected F1 females. Substance-induced signs of developmental toxicity were observed in progeny of the F0 parents at 500 ppm. The administration led to impairments of pup body weight data and causally related pup organ weight changes occurred in the high-dose progeny of the F0 parental rats. Furthermore, a delay in preputial separation/vaginal opening in the selected F1 males/females was noted as a sign of a general delay in physical development. Dose levels of 10 or 80 ppm did not induce any indications of developmental toxicity. Therefore, the NOAEL for reproductive performance and fertility is 500 ppm (about 40 mg/kg bw/day) for the F0 parental rats. The NOAEL for general, systemic toxicity of the test substance is 10 ppm (about 1 mg/kg bw/day) for the F0 parental males and females. The NOAEL for developmental toxicity (growth and development of the offspring) could be fixed at 80 ppm (about 7.6 mg/kg bw/day) for the F1 progeny. Thus, indications for developmental toxicity occurred only at a dose, which was also toxic to the parental animals (see also RSS).
However, both substances were also tested in pre-natal developmental toxicity studies, where they were shown to lack any potential to adversely influence the development of the offspring, nor to disturb organogenesis at any stage.
2-butyne-1,4-diol was administered by oral gavage to groups of 25 pregnant rats at dose levels of 0, 10, 40, and 80 mg/kg bw/day for ten consecutive days (GD 6-15). The test item caused overt signs of maternal toxicity at 80 mg/kg bw substantiated by reduced food consumption, impaired body weight gains, an intercurrent death of one dam, and some adverse clinical signs (all these findings occurred at the beginning of the treatment period). Marginal signs of developmental toxicity were observed at the highest dose level (80 mg/kg bw/day), substantiated by an increased number of affected fetuses/litter with accessory 14th rib(s), a skeletal variation. No substance-related effects on dams, gestational parameters or fetuses were observed at 40 mg/kg bw/day and 10 mg/kg bw/day. No substance-induced teratogenic effects were observed up to and including the dose of 80 mg/kg bw/day and there were no signs of embryo-/fetotoxicity at 40 mg/kg bw/day and 10 mg/kg bw. The maternal as well as developmental NOAELs were determined to be 40 mg/kg bw/day (presented as supporting information in IUCLID chapter 7.8.2).
In comparison, propargyl alcohol was administered to pregnant Wistar rats daily by gavage from implantation to one day prior to the expected day of parturition (GD 6-19) to evaluate its potential maternal and pre-natal developmental toxicity (OECD 414). Generally, clinical observations including food consumption and body weight/body weight gain revealed no toxicologically relevant differences between the animals receiving 1, 4, and 12 mg/kg bw/day and controls. Regarding pathology, the target organ was the liver. Increased absolute and relative liver weights in the mid-and high dose groups were regarded as treatment-related but not adverse. They were above the historical control data (absolute: 10.81-11.45 g; relative: 4.55-4.73). Since the weight increase was only minimal, it was regarded as an adaptive change. No differences of toxicological relevance between the control and the treated groups (1, 4, or 12 mg/kg bw/day) were determined for any reproductive parameters, such as conception rate, mean number of corpora lutea, mean number of implantations, as well as pre- and postimplantation loss. Similarly, no influence of the test substance on fetal weight and sex distribution of the fetuses was noted at any dose. Overall, there was no evidence for toxicologically relevant adverse effects of the test substance on fetal morphology at any dose. Under the conditions of this pre-natal developmental toxicity study, the oral administration of propargyl alcohol to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (GD 6-19) at doses as high as 12 mg/kg bw/day caused neither evidence of maternal nor developmental toxicity. In conclusion, the no observed adverse effect level (NOAEL) for maternal and pre-natal developmental toxicity is the highest tested dose of 12 mg/kg bw/day.
All currently available data suggest propargyl alcohol not be a reprotoxic agent, neither in terms of bearing the potential to adversely affecting fertility nor to cause any developmental toxicity. Furthermore, non of the repeated dose toxicity studies with propargyl alcohol revealed any histological changes in the testes or ovaries (US EPA, 1987): Male and female Crl:CD(SD)BR rats (n = 20/sex/group) were dosed orally (gavage) with 0, 5, 15, or 50 mg/kg bw/day of propargyl alcohol daily for 13 weeks. Rats were sacrificed on days 91 or 92 after dosing. Parameters examined included clinical signs, body and organ weight changes, food consumption, ophthalmology, haematology, blood chemistry and histological evaluations. Treatment-related mortality was reported for 4/30 males in the high-dose group. The most prevalent clinical sign was salivation, occurring mainly at 50 mg/kg bw/day. Body weights were significantly lower in the high-dose animals. Haematological changes observed in the high-dose animals comprised decreased haemoglobin, MCV (also at 15 mg/kg bw/day), MCH, and mean corpuscular haemoglobin concentration (MCHC) values. Enzyme changes characteristic of liver damage were seen in the mid- and high-dose animals. These changes included significantly increased ALAT, ASAT, LDH, and ALP serum activities. Moreover, decreased glucose, sodium, total cholesterol, total protein, albumin, globulin, and creatinine serum levels were seen, whereas inorganic phosphate and total bilirubin serum levels were significantly higher. The haematological and blood chemistry changes were considered to be treatment-related. Absolute and relative liver and kidney weights were significantly increased in males and/or females at 15 and 50 mg/kg bw/day. At 5 mg/kg bw/day, mean absolute and relative liver weights were higher compared to controls, but statistical significance was not reached. Macroscopic findings were confined to the liver (15 and 50 mg/kg bw/day) and the stomach (50 mg/kg bw/day). Hepatocytic megalocytosis with a less prominent proliferation of the bile ducts and cytoplasmic vacuolation of hepatocytes was observed in the majority of rats in the mid- and high-dose groups. In the low-dose group, megalocytosis was seen only in one rat treated for 3 months. Karyomegaly of renal tubular epithelial cells was reported to occur in a dose-response fashion in the mid- and high-dose groups, but not in the low-dose group. Treatment-related effects at 15 mg/kg bw/day included increased liver weights in both genders, increased kidney weights in females, and megalocytosis of the liver after 13 weeks of dosing. The daily oral administration of 5 mg/kg bw/day of propargyl alcohol produced no apparent treatment-related effects and hence this dose level was considered a NOAEL for subchronic oral exposure.
The dose setting for a putative extended one-generation toxicity study (OECD 443) would most probably be also in the same range as that used in the studies above, meaning that the high dose level would be at 15 mg/kg bw/day, followed by 5 mg/kg bw/day and 2 mg/kg bw/day. None of those dosages with the exemption of specific target organ toxicity were able to produce any effects connectable with reproductive toxicity.

Annex XI, section 1.2 of the REACh Regulation sets the following conditions for a weight of evidence approach:
“There may be sufficient weight of evidence from several independent sources of information leading to the assumption/conclusion that a substance has or has not a particular dangerous property, while the information from each single source alone is regarded insufficient to support this notion. Where sufficient weight of evidence for the presence or absence of a particular dangerous property is available:
- further testing on vertebrate animals for that property shall be omitted (…)”.

Taking all available data of propargyl alcohol itself in combination with those available for the read-across analogue 2-butyne-1,4-diol together in combination with the lack of information gain via conduction of a further study, the Registrant is of the opinion that the anticipated weight of evidence approach meets the conditions of REACh annex XI, section 1.2. Omitting further developmental toxicity testing will also be in line with animal welfare as laid down in Article 25 of the REACh Regulation.

Reason / purpose for cross-reference:

data waiving: supporting information

Reason / purpose for cross-reference:

data waiving: supporting information

Reason / purpose for cross-reference:

data waiving: supporting information

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

40 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

There is only an OECD guideline 421 study available for propargyl alcohol, but no one-generation reproductive toxicity study (OECD 443). However, this data gap can be closed by cross-reading to an extended OECD 415 conducted with 2-butyne-1,4-diol (CAS 110-65-6) and using all currently available information on propargyl alcohol itself in an holistic weight of evidence approach while waiving the above mentioned standard information requirement (according to REACh annex XI, section 1.2).

The read-across to 2-butyne-1,4-diol is justified for the following reasons:

The target chemical propargyl alcohol and its source chemical 2-butyne-1,4-diol (CAS 110-65-6) are considered read-across analogues based on structural similarity and similar physico-chemical and toxicological properties. The common structural features of the two substances are: a common functional methylol group; the methylol group(s) is/are bound to an alkyne structure; there are no elements other than carbon, hydrogen and oxygen; identical structures except for one additional methylol group on the alkyne structure of the source chemical 2-butyne-1,4-diol; similar molecular weights, both far below 500 daltons, qualifying as “low molecular weight” compounds. For a detailed read across justification see also attached assessment report (IUCLID chapters 7.8.1 and 13).

 

The effects of propargyl alcohol on fertility of parental animals and development of their offspring were determined in an OECD 421 screening study, in which groups of ten male and ten female rats were treated orally via gavage at dose levels of 0, 5, 15, and 45 mg/kg bw in order to observe possible effects on the integrity and performance of the reproductive system of both sexes. Three animals (two males and one female) from the high-dose group died during the first week of treatment. Before their death, these animals and one additional high-dose female showed an impairment of their general state of health. A significant reduction of food consumption and body weight gains were also reported in animals of the high-dose group. After one week, the treatment was discontinued and the high-dose group animals were sacrificed and assessed by gross pathology. The premature death of the high-dose animals might be explained by acute toxic effects mediated by propargyl alcohols’ general toxicity (LD₅₀= 56.4 mg/kg bw vs. 45 mg/kg bw administered to high-dose animals). No substance-related findings were observed during gross pathology. No signs of general, systemic toxicity and no adverse effects on fertility and reproductive performance were noted in the F0 parental animals of both sexes of the 5 and 15 mg/kg bw/day groups. No signs of developmental toxicity were observed in the F1 pups of the 5 and 15 mg/kg bw/day groups. Therefore, the NOAEL for general, systemic toxicity, reproductive performance, fertility of the F0 parental rats and the NOAEL for developmental toxicity in the F1 progeny was 15 mg/kg bw/day. At 45 mg/kg bw/day marked toxicity and lethality was noted. These findings justify the premature termination of this dose group, since they precluded a meaningful assessment of fertility and reproduction in these animals (BASF, 2006).

 

In an extended one-generation reproduction study (OECD 415) 2-butyne-1,4-diol was administered to 25 male and 25 female rats in drinking water at nominal dose levels of 0, 10, 80, or 500 ppm (approximately 0, 1.0, 7.6, or 40 mg/kg bw). The study was extended by examinations (estrous cycle, sperm parameters, organ weight determination in selected pups and parental animals, extended histology, signs of sexual maturation) that are required in the test guideline OECD 416. At least 76 days after the beginning of treatment, F0 animals were mated to produce a litter (P). The F1 pups were raised up until day 21 post-partum (p.p.). Thereafter, the F1 weanlings with the exception of one male and one female pup/litter and all F0 adult animals were sacrificed. The selected F1 weanlings were reared until sexual maturation occurred and were killed thereafter. Drinking water containing 2-butyne-1,4-diol was administered continuously throughout the study. There were no indications from the clinical and pathological examinations, that the administration of 2-butyne-1,4-diol had adverse effects on reproductive performance or fertility of the F0 parental animals of all substance-treated groups. Estrous cycle data, mating behavior, conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights, gross and histopathological findings of these organs revealed no substance-related adverse effects. Most of the F0 parental rats proved to be fertile. The scattered occurrence of individual infertile rats throughout the different dose groups did not suggest any relation to treatment. Signs of general, systemic toxicity in the F0 parental generation were confined to the rats of the 80 and 500 ppm groups. However, there were no substance-related mortalities in any of the F0 parental animals. This might be explained by changed absorption kinetics of 2-butyne-1,4-diol as a result of drinking water administration as compared with a bolus administration of propargyl alcohol in the above mentioned screening study. Reduced water consumption during premating in the F0 parental rats as well as during gestation and lactation in the F0 females were observed at 500 ppm. Impairments in body weight/body weight gain were noted for the F0 females during premating, gestation and lactation with concurrent lowered food consumption. Concerning pathology, substance-induced statistically significantly increased absolute and relative kidney weights (both F0 sexes) and liver weights (F0 females) as well as statistically significantly decreased absolute and relative weights of the adrenal glands and thymus in F0 females occurred at 500 ppm. At 80 ppm impaired water consumption was noted during premating (both F0 sexes) and gestation (F0 females), while pathology revealed statistically significantly increased absolute and relative kidney (both F0 sexes) and liver weights (F0 females). Moreover, the examinations of the selected F1 animals performed until sexual maturation indicated signs of general systemic toxicity at 500 ppm in form of reduced water consumption (both sexes), impaired body weight/body weight gain in the selected F1 males with concurrent reductions in food consumption as well as reduced body weights in the selected F1 females. Substance-induced signs of developmental toxicity were observed in progeny of the F0 parents at 500 ppm. The administration led to impairments of pup body weight data and causally related pup organ weight changes occurred in the high-dose progeny of the F0 parental rats. Furthermore, a delay in preputial separation/vaginal opening in the selected F1 males/females was noted as a sign of a general delay in physical development. Dose levels of 10 or 80 ppm did not induce any indications of developmental toxicity. Therefore, the NOAEL for reproductive performance and fertility is 500 ppm (about 40 mg/kg bw/day) for the F0 parental rats. The NOAEL for general, systemic toxicity of the test substance is 10 ppm (about 1 mg/kg bw/day) for the F0 parental males and females. The NOAEL for developmental toxicity (growth and development of the offspring) could be fixed at 80 ppm (about 7.6 mg/kg bw/day) for the F1 progeny. Thus, indications for developmental toxicity occurred only at a dose, which was also toxic to the parental animals (BASF, 1999).

Additionally, non of the repeated dose toxicity studies with propargyl alcohol revealed any histological changes in the testes or ovaries (US EPA, 1987): Male and female Crl:CD(SD)BR rats (n = 20/sex/group) were dosed orally (gavage) with 0, 5, 15 or 50 mg/kg bw of propargyl alcohol daily for 13 weeks. Rats were sacrificed on days 91 or 92 after dosing. Parameters examined included clinical signs, body and organ weight changes, food consumption, ophthalmology, haematology, blood chemistry and histological evaluations. Treatment-related mortality was reported for 4/30 males in the high-dose group. The most prevalent clinical sign was salivation, occurring mainly at 50 mg/kg bw. Body weights were significantly lower in the high-dose animals. Haematological changes observed in the high-dose animals comprised decreased haemoglobin, MCV (also at 15 mg/kg bw), MCH, and mean corpuscular haemoglobin concentration (MCHC) values. Enzyme changes characteristic of liver damage were seen in the mid- and high-dose animals. These changes included significantly increased ALAT, ASAT, LDH, and ALP serum activities. Moreover, decreased glucose, sodium, total cholesterol, total protein, albumin, globulin, and creatinine serum levels were seen, whereas inorganic phosphate and total bilirubin serum levels were significantly higher. The haematological and blood chemistry changes were considered to be treatment-related. Absolute and relative liver and kidney weights were significantly increased in males and/or females at 15 and 50 mg/kg bw/day. At 5 mg/kg bw, mean absolute and relative liver weights were higher compared to controls, but statistical significance was not reached. Macroscopic findings were confined to the liver (15 and 50 mg/kg bw) and the stomach (50 mg/kg bw). Hepatocytic megalocytosis with a less prominent proliferation of the bile ducts and cytoplasmic vacuolation of hepatocytes was observed in the majority of rats in the mid- and high-dose groups. In the low-dose group, megalocytosis was seen only in one rat treated for 3 months. Karyomegaly of renal tubular epithelial cells was reported to occur in a dose-response fashion in the mid- and high-dose groups, but not in the low-dose group. Treatment-related effects at 15 mg/kg bw included increased liver weights in both genders, increased kidney weights in females, and megalocytosis of the liver after 13 weeks of dosing. The daily oral administration of 5 mg/kg bw/day of propynol produced no apparent treatment-related effects and hence this dose level was considered a NOAEL for subchronic oral exposure to propargyl alcohol.

The dose setting for a putative extended one-generation toxicity study (OECD 443) would most probably be also in the same range as that used in the studies above, meaning that the high dose level would be at 15 mg/kg bw/day, followed by 5 mg/kg bw/day and 2 mg/kg bw/day. None of those dosages with the exemption of specific target organ toxicity were able to produce any effects connectable with reproductive toxicity.

Annex XI, section 1.2 of the REACh Regulation sets the following conditions for a weight of evidence approach:

“There may be sufficient weight of evidence from several independent sources of information leading to the assumption/conclusion that a substance has or has not a particular dangerous property, while the information from each single source alone is regarded insufficient to support this notion. Where sufficient weight of evidence for the presence or absence of a particular dangerous property is available:

- further testing on vertebrate animals for that property shall be omitted (…)”.

Taking all available data of propargyl alcohol itself in combination with those available for the read-across analogue 2-butyne-1,4-diol together in combination with the lack of information gain via conduction of a further study, the Registrant is of the opinion that the anticipated weight of evidence approach meets the conditions of REACh annex XI, section 1.2. Omitting further developmental toxicity testing will also be in line with animal welfare as laid down in Article 25 of the REACh Regulation.

Effects on developmental toxicity

Description of key information

Propargyl alcohol did not cause developmental toxicity in an OECD 414 guideline study in rats.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The mean values of the low-, mid- and high-dose samples (1, 4 and 12 mg/kg bw/d) were below the expected range of 90% to 110% of the nominal concentrations. For the low-, mid- and high-dose, three samples each were measured. One out of
three analytical value of the high-dose samples was within the expected range (sample no. 10: 91.2%). The mean values of 54, 65 and 75% of the nominal concentrations correspond to an actual low-, mid- and high dose of 0.5, 2.6 and 9 mg/kg bw/d, respectively. This did not affect the validity of the study. However, in the robust study summary, the nominal doses were used.

Duration of treatment / exposure:

GD 6-19

Frequency of treatment:

once daily

Dose / conc.:

1 mg/kg bw/day (nominal)

Dose / conc.:

4 mg/kg bw/day (nominal)

Dose / conc.:

12 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25

Control animals:

yes

Details on study design:

Dose rational
In a maternal toxicity study, 7 pregnant Wistar rats per group received doses of 0, 8 and 25 mg/kg bw/d 2-propyn-1-ol orally by gavage over 14 days from gestation day (GD) 6 through GD 19. The study aimed to select the dose levels for the subsequent OECD 414 study.
Clinical examinations including body weight, food consumption, uterus and carcass weight and clinical pathology (clinical chemistry and hematology) were assessed and showed no relevant changes besides lower total protein levels (albumins and globulins) at 25 mg/kg bw/d. At 25 mg/kg bw/d, a statistically significant increase in absolute (+29%) and relative (+30%) liver weights was observed. Histopathological evaluation of these animals showed hypertrophy (n=6), nuclear inclusions (n=2), single cell necrosis (n=2) and multifocal necrosis (n=1) in liver. At 8 mg/kg bw/d, organ weights showed a non-statistically significant increase in absolute (107%) and a statistically significant increase in relative (110%) liver weights. A histopathological examination of the livers of that group showed no effects.

Due to the clear adverse findings in the livers at 25 mg/kg bw/d, half of the dose level was selected for the OECD 414 as high dose: 12 mg/kg bw/d. This dose was assumed to be appropriate since, it was higher than 8 mg/kg bw/d with slight findings only, but below the dosage of 25 mg/kg bw/d resulting in pronounced maternal toxicity.

Based on the available data the following dose levels were chosen for the present prenatal developmental toxicity study in Wistar rats:
1 mg/kg body weight/day: as low-dose level
4 mg/kg body weight/day: as mid-dose level
12 mg/kg body weight/day: as high-dose level

The oral route was selected since this has proven to be suitable for the detection of a toxicological hazard.

Maternal examinations:

CLINICAL EXAMINATIONS OF THE DAMS
Mortality
A check was made twice a day on working days or once a day on Saturdays, Sundays or on public holidays (GD 0-20).

Clinical symptoms
A cage-side examination was conducted at least once daily before and after treatment period (GD 0-5 and 20). During treatment period (GD 6-19) all rats were checked daily for any signs of morbidity, pertinent behavioral changes and/or signs of overt toxicity before administration as well as within 2 hours and within 5 hours after administration.

Food consumption
The consumption of food was recorded for the intervals GD 0-1, 1-3, 3-6, 6-8, 8-10, 10-13, 13-15, 15-17, 17-19 and 19-20.

Body weight data
All animals were weighed on GD 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20. The body weight change of the animals was calculated based on the obtained results.

Corrected (net) body weight gain
Furthermore, the corrected body weight gain was calculated after terminal sacrifice (terminal body weight on GD 20 minus weight of the unopened uterus minus body weight on GD 6).

TERMINAL EXAMINATIONS OF THE DAMS
Cesarean section
On GD 20, the dams were sacrificed under isoflurane anesthesia by decapitation, in randomized order. After the dams had been sacrificed, they were necropsied and assessed for gross pathology, special attention being given to the reproductive organs. The uteri and the ovaries were removed and the following data were recorded:
- Weight of the unopened uterus
- Number of corpora lutea
- Number and distribution of implantation sites classified as:
• Live fetuses
• Dead implantations:
a) Early resorptions (only decidual or placental tissues visible or according to SALEWSKI from uteri from apparently non-pregnant animals and the empty uterus horn in the case of single horn pregnancy)
b) Late resorptions (embryonic or fetal tissue in addition to placental tissue visible)
c) Dead fetuses (hypoxemic fetuses which did not breathe spontaneously after the uterus had been opened)
After the weight of the uterus had been determined, all subsequent evaluations of the dams and the gestational parameters were conducted by technicians unaware of treatment group in order to minimize bias. For this purpose animal numbers were encoded.

Pathology
Organ weights
The following weights were determined in all animals sacrificed on schedule:
1. Liver
The carcass weights (GROSSE-System) were transferred to the ACOPAT-System to calculate the relative organ weights.

Organ/tissue fixation
The following organs or tissues were fixed in 4% neutral-buffered formaldehyde solution or in modified Davidson’s solution:
1. All gross lesions
2. Liver

No further examinations or procedures were performed in the study.

Ovaries and uterine content:

see maternal examinations

Fetal examinations:

All fetal analyses were conducted by technicians unaware of the treatment group, in order to minimize bias.

Examinations of the fetuses after dissection from the uterus
At necropsy each fetus was weighed, sexed, and external tissues and all orifices were examined macroscopically. The sex was determined by observing the distance between the anus and the base of the genitalia. Furthermore, the viability of the fetuses and the condition of placentas, umbilical cords, fetal membranes, and fluids were examined. The placentas were weighed and their individual weights were recorded. Thereafter, the fetuses were sacrificed by a subcutaneous injection of pentobarbital (Narcoren®; dose: 0.1 mL/fetus). After these examinations, approximately one half of the fetuses per dam were eviscerated, skinned and fixed in ethanol; the other half was placed in Harrison’s fluid for fixation.

Soft tissue examination of the fetuses
The fetuses fixed in Harrison’s fluid were examined for any visceral findings according to the method of BARROW and TAYLOR. After this examination these fetuses were discarded.

Skeletal examination of the fetuses
The skeletons of the fetuses fixed in ethanol were stained according to a modified method of KIMMEL and TRAMMELL. Thereafter, the skeletons of these fetuses were examined under a stereomicroscope. After this examination the stained fetal skeletons were retained individually.

Clinical signs:

no effects observed

Description (incidence and severity):

No clinical signs or changes of general behavior, which may be attributed to the test substance, were detected in any female at dose levels of 1, 4 or 12 mg/kg bw/d during the entire study period.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

There were no test substance-related or spontaneous mortalities in any females of all test groups (0, 1, 4 or 12 mg/kg bw/d).

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The mean body weights and the average body weight gain of the low-, mid- and high-dose dams (1, 4 and 12 mg/kg bw/d) were generally comparable to the concurrent control group throughout the entire study period.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

The mean food consumption of the dams in test groups 1, 2 and 3 (1, 4 and 12 mg/kg bw/d) was comparable to the concurrent control group throughout the entire study period.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

When compared to control group 0 (set to 100%), the mean absolute weights of the livers were significantly increased in test groups 2 and 3. When compared to control group 0 (set to 100%), the mean relative weights of the livers were significantly increased in test groups 2 and 3.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

All findings occurred either individually or were biologically equally distributed over control and treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.

Neuropathological findings:

not examined

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

not examined

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined

Changes in number of pregnant:

effects observed, non-treatment-related

Description (incidence and severity):

Only pregnant dams were used for the calculations of mean maternal food consumption, body weight and body weight change. Only pregnant dams with scheduled sacrifice (GD 20) were used for the calculation of mean gravid uterine weights, corrected (net) body weight gain and summary of reproduction data. The following females were excluded from the above-mentioned calculations:
Test group 0 (0 mg/kg bw/d):
• female No. 8 – not pregnant

Test group 1 (1 mg/kg bw/d):
• females Nos. 26, 42 and 43 – not pregnant

Test group 2 (4 mg/kg bw/d):
• female No. 68 – not pregnant

Test group 3 (12 mg/kg bw/d):
• females Nos. 76 and 90 – not pregnant

Other effects:

no effects observed

Description (incidence and severity):

Weight of the placentae
The mean placental weights of the low-, mid- and high-dose groups were comparable to the corresponding control group.

Dose descriptor:

NOAEL

Effect level:

12 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks on result:

not determinable due to absence of adverse toxic effects

Abnormalities:

no effects observed

Fetal body weight changes:

not examined

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not examined

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Description (incidence and severity):

The sex distribution of the fetuses in test groups 1-3 (1, 4 and 12 mg/kg bw/d) was comparable to the control fetuses.

Changes in litter size and weights:

effects observed, non-treatment-related

Description (incidence and severity):

The mean fetal weights of test groups 1, 2 and 3 were not influenced by the test substance and did not show any biologically relevant differences in comparison to the control group. The marginally but statistically significantly higher male fetal weight in test group 3 (3.8 g) is within the historical control range (HCD: 3.7 g, [2.8-4.5]) and, therefore, not considered to be of any biological relevance.

Changes in postnatal survival:

not examined

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

One fetus each in test groups 1, 2 and 3 (1, 4 and 12 mg/kg bw/d) had external malformations, In two cases, these external malformations were seen in combination with either soft tissue or skeletal malformations. None of these malformations were considered to be related to the treatment since they showed no relation to dose and were scattered observations in individual fetuses with no specific ontogenetic pattern. The total incidence of external malformations in treated animals did not differ significantly from the concurrent control group and was comparable to the historical control data.

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Skeletal malformations were noted in three fetuses of the low-dose group (1 mg/kg bw/d) and one fetus of the mid-dose group (4 mg/kg bw/d). One low-dose fetus had associated external malformations. Although the overall incidence of skeletal malformations was statistically significantly increased in test group 1, the individual malformations were without relation to dose and the overall incidences were clearly within the historical control range (mean value: 0.9 %, range: 0.0 - 3.1%). Thus, the findings were not considered to be treatment-related.

For all test groups, skeletal variations of different bone structures were observed, with or without effects on corresponding cartilages. The observed skeletal variations were related to several parts of fetal skeletons and appeared in the majority of cases without a relation to dose. The overall incidences of skeletal variations were comparable to the historical control data.

The finding ‘incomplete ossification skull; unchanged cartilage’ was statistically significantly increased in affected fetuses/litter in test groups 2 and 3 and in litter incidence (39%) in test group 3. However, all values were clearly inside the historical control range (see table above and HCD of litter incidence: mean 28.5%, [4 - 56%]). Therefore, the finding was not assessed as treatment-related. The findings ‘dumbbell ossification of thoracic centrum’ and ‘misshapen sacral vertebra’ were not related to dose and the mean values were below or close to the mean of the historical control data. Therefore, both findings were not assessed as treatment-related. The finding ‘incomplete ossification of basisphenoid’ was statistically significantly increased in test group 1 (litter incidence: n=21**, 95%). The value was slightly outside of the range of the historical control data (mean 51.4%, [20.8 - 87.5%]). However, the increase was not doserelated and, therefore, it was not assessed as treatment-related.

Additionally, some isolated cartilage findings without impact on the respective bony structures, which were designated as unclassified cartilage observations, occurred in all test groups. The observed unclassified cartilage findings were related to the skull, the vertebral column, the ribs and the sternum and did not show any relation to dose and were not assessed as treatment-related.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

One fetus each of test groups 2 and 3 (4 and 12 mg/kg bw/d) had soft tissue malformations. For one affected fetus, these soft tissue findings were seen in combination with an external malformation. The finding right-sided aortic arch was not related to dosing and, therefore, not assessed as treatment-related. The malformations hydronephrosis and hydroureter can be found in the historical control data in comparable frequencies and, therefore, they were not assessed as treatment-related. The overall incidences of soft tissue malformations were comparable to those found in the historical control data.

Four soft tissue variations, i.e. malpositioned subclavian artery origin, short innominate, dilated renal pelvis and dilated ureter, were detected in all test groups including the controls. The incidences of these variations were neither statistically significantly nor dose-dependently increased in the treated groups and, therefore, not considered biologically relevant.

Dose descriptor:

NOAEL

Effect level:

> 12 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Abnormalities:

no effects observed

Developmental effects observed:

no

There were noted external, soft tissue and skeletal malformations in test groups 1, 2 and 3 (1, 4 and 12 mg/kg bw/d). However, the low-dose mean affected fetuses per litter (mean 1.2%) were statistically significantly different from concurrent control. All of these individual malformations (mandibular micrognathia, microstomia, severely malformed skull bones, misshapen tuberositas deltoidea) of test group 1 were scattered observations in individual fetuses of different litters. Some of them are present in the historical control data. Due to the absent relation to dose, an association of these findings to the treatment is not assumed. Three fetuses were multiple malformed in each test group. Male low-dose fetus No. 47-10 (1 mg/kg bw/d) had a mandibular micrognathia and microstomia, comprising severely malformed skull bones during skeletal examination. For male mid-dose fetus No. 57-03 (4 mg/kg bw/d) a gastroschisis and a right-sided aortic arch were recorded, while high-dose female fetus No. 98-02 (12 mg/kg bw/d) had a hydronephrosis and a hydroureter. No ontogenetic pattern is recognizable for these individual malformations nor was there any cluster of any of these individual malformations seen in the other offspring of these test groups. Most of them can be found in the historical control data of the rat strain. An association of these,findings to the treatment is not assumed. Further malformations, i.e. meningocele (in test group 3) and misshapen tuberositas deltoidea (in test group 2), were observed in individual fetuses, were not related to dose and can mostly be found in the historical control data. An association of these findings to the treatment is also not assumed.

External variations did not occur in any of the fetuses of the study. Some soft tissue variations and a range of skeletal variations were noted in all test groups including the controls. In test groups 1-3, all statistically significantly increased fetal skeletal variations were within the historical control range. None of the incidences showed a relation to dose. The skeletal variations are equally distributed about the different test groups, if normal biological variation is taken into account, and can be found in the historical control data at a comparable frequency.

No unclassified external and unclassified soft tissue observations were recorded for any of the fetuses in this study. A spontaneous origin is assumed for the unclassified skeletal cartilage observations which were observed in several fetuses of test groups 0, 1, 2 and 3 (0, 1, 4 and 12 mg/kg bw/d). The distribution and type of these findings do not suggest any relation to treatment. Finally, fetal examinations revealed that there is no effect of the compound on the respective morphological structures up to the highest dose tested (12 mg/kg bw/d).

Conclusions:

Under the conditions of this prenatal developmental toxicity study, the oral administration of 2-propyn-1-ol to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (GD 6-19) at doses as high as 12 mg/kg bw/d caused neither evidence of maternal nor developmental toxicity. In conclusion, the no observed adverse effect level (NOAEL) for maternal and prenatal developmental toxicity is the highest tested dose of 12 mg/kg bw/d.

Executive summary:

In a prenatal developmental toxicity study, the test substance 2-propyn-1-ol was administered to pregnant Wistar rats daily by gavage from implantation to one day prior to the expected day of parturition (GD 6-19) to evaluate its potential maternal and prenatal developmental toxicity. Generally, clinical observations including food consumption and body weight/body weight gain revealed no toxicologically relevant differences between the animals receiving 1, 4 and 12 mg/kg bw/d 2-propyn-1-ol and controls.

Regarding pathology, the target organ was the liver. Increased absolute and relative liver weights in test groups 2 and 3 were regarded as treatment-related but not adverse. They were above the historical control data (absolute: 10.81 – 11.45 g; relative: 4.55 – 4.73). Since the weight increase was only minimal, it was regarded as an adaptive change.

No differences of toxicological relevance between the control and the treated groups (1, 4 or 12 mg/kg bw/d) were determined for any reproductive parameters, such as conception rate, mean number of corpora lutea, mean number of implantations, as well as pre- and postimplantation loss. Similarly, no influence of the test substance on fetal weight and sex distribution of the fetuses was noted at any dose. Overall, there was no evidence for toxicologically relevant adverse effects of the test substance on fetal morphology at any dose.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

12 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In a pre-natal developmental toxicity study according to OECD guideline 414, 2-propyn-1-ol was administered to pregnant Wistar rats daily by gavage from implantation to one day prior to the expected day of parturition (GD 6-19) to evaluate its potential maternal and prenatal developmental toxicity. Generally, clinical observations including food consumption and body weight/body weight gain revealed no toxicologically relevant differences between the animals receiving 1, 4, and 12 mg/kg bw/d 2-propyn-1-ol and controls. Regarding pathology, the target organ was the liver. Increased absolute and relative liver weights in test groups 2 and 3 were regarded as treatment-related but not adverse. They were above the historical control data (absolute: 10.81 – 11.45 g; relative: 4.55 – 4.73). Since the weight increase was only minimal, it was regarded as an adaptive change. No differences of toxicological relevance between the control and the treated groups (1, 4 or 12 mg/kg bw/d) were determined for any reproductive parameters, such as conception rate, mean number of corpora lutea, mean number of implantations, as well as pre- and postimplantation loss. Similarly, no influence of the test substance on fetal weight and sex distribution of the fetuses was noted at any dose. Overall, there was no evidence for toxicologically relevant adverse effects of the test substance on fetal morphology at any dose.

Under the conditions of this pre-natal developmental toxicity study, the oral administration of 2-propyn-1-ol to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (GD 6-19) at doses as high as 12 mg/kg bw/d caused neither evidence of maternal nor developmental toxicity. In conclusion, the no observed adverse effect level (NOAEL) for maternal and prenatal developmental toxicity is the highest tested dose of 12 mg/kg bw/d (BASF, 2017).

As supporting information, the results of a pre-natal developmental toxicity study according to OECD guideline 414 with the read-across substance 2-butyne-1,4-diol is also discussed: in that study 414, 2-butyne-1,4-diol was administered by oral gavage to groups of 25 pregnant rats at dose levels of 0, 10, 40, and 80 mg/kg bw for ten consecutive days (d6 -15 post-coitum). The test item caused overt signs of maternal toxicity at 80 mg/kg bw substantiated by reduced food consumption, impaired body weight gains, an intercurrent death of one dam, and some adverse clinical signs (all these findings occurred at the beginning of the treatment period). Marginal signs of developmental toxicity were observed at the highest dose level (80 mg/kg bw), substantiated by an increased number of affected fetuses/litter with accessory 14th rib(s), a skeletal variation. No substance-related effects on dams, gestational parameters or fetuses were observed at 40 mg/kg bw and 10 mg/kg bw. No substance-induced teratogenic effects were observed up to and including the dose of 80 mg/kg bw and there were no signs of embryo-/fetotoxicity at 40 mg/kg bw and 10 mg/kg bw. The maternal as well as developmental NOAELs were determined to be 40 mg/kg bw (BASF, 1995).

The read-across is justified for the following reasons:

The target chemical propargyl alcohol and its source chemical 2-butyne-1,4-diol (CAS 110-65-6) are considered read-across analogues based on structural similarity and similar physico-chemical and toxicological properties. The common structural features of the two substances are: a common functional methylol group; the methylol group(s) is/are bound to an alkyne structure; there are no elements other than carbon, hydrogen and oxygen; identical structures except for one additional methylol group on the alkyne structure of the source chemical 2-butyne-1,4-diol; similar molecular weights, both far below 500 daltons, qualifying as “low molecular weight” compounds. For a detailed read across justification see also attached assessment report (IUCLID chapters 7.8.1 and 13).

The comparison of the results of the both pre-natal developmental toxicity studies suggests that the substances are of very similar potency, with any differences in toxicity likely to be the result of experimental variation (e.g. dose selection and especially, duration of administration as well as application route). Repeated administration of both alkyne alcohols leads to systemic toxicity primarily affecting the liver, kidney, and the hematological system (spleen) for both substances occurring in the dose range of 10-15 mg/kg bw. Additionally, the NOAELs determined are in the same range. Therefore, the results of both OECD 414 as well as the extended OECD 415 with 2-butyne-1,4-diol seem to be appropriate to support the conclusions drawn at the endpoint repeated dose toxicity and to be used to cover the endpoint reproductive toxicity with regard to fertility.

Justification for classification or non-classification

Based on the available data propargyl alcohol is not subject to classification and labelling for developmental or reproduction toxicity (sexual function, fertility and lactation) according to EU Regulation No. 1272/2008.