Isopropylamine

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

NOAEC = 500 mg/m3: No adverse effect on reproductive performance in the P-generation and no adverse effects on development of the progeny of the P-generation (F1)

Link to relevant study records

Reference

Endpoint:

one-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

1-generation study. Treated males were mated to untreated female and vice versa.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: (P) 54 days; (F1) from birth
- Weight at study initiation: (P) Males: 241 - 300 g; Females: 163 - 207 g
- Fasting period before study: no

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-23
- Humidity (%): 35-60
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

air

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: maximally 7 d
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as [day 0 / day 1] of pregnancy
- Female reproduction (males unexposed): After 7 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Male fertility (females unexposed): After 7 days of unsuccessful pairing replacement of first female by another unexposed female

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Routinely sampled five times per exposure at approximately one hour intervals. Test atmosphere was drawn through a MIRAN 1A General Purpose Gas Analyzer

Duration of treatment / exposure:

- Duration of test: up to 15 weeks (males)
- Duration of test: 17-18 weeks (females)

Frequency of treatment:

untreated + treated males: Six hours per day, 5 days per week
treated and untreated females: Six hours per day, 5 days per week (premating and mating period)
treated females: Six hours per day, 7 days per week (during gestation period)

Dose / conc.:

20 mg/m³ air (analytical)

Dose / conc.:

100 mg/m³ air (analytical)

Dose / conc.:

499 mg/m³ air (analytical)

No. of animals per sex per dose:

Twenty male rats per treatment
- Twenty-five female rats per treatment

Control animals:

yes

Parental animals: Observations and examinations:

ADMINISTRATION / EXPOSURE:
- Premating period: 10.5 weeks
- Route of administration: inhalation
- Post exposure period: from day 21 of gestation until day 21 of lactation
- Exposure duration: 6 hours/day, 5 days/week (after mating 7 days/week until day 20 of gestation)
- Preparation of particles: using a Laskin-style nebulizer
- Air changes: 12/hour

STANDARDIZATION OF LITTERS:
- On day 4 of lactation litters were culled to 4 pups/sex

PARAMETERS ASSESSED IN PARENTS:
- Detailed observations and body weight were assessed on a weekly basis
- Mortality/clinical observations: daily during and after exposure
- Body weight females: weekly until mating, thereafter on day 0, 6, 13 and 20 of gestation and on day 0, 4, 7,
14 and 21 of lactation
- Number of live pups at delivery
- After termination, females were examined and the number of implantations and the number of corpora lutea
were determined

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Gross necropsy of dams and pups on day 21 of lactation
- Histopathology on tissues of pups of control and high dose group

Oestrous cyclicity (parental animals):

not examined

Sperm parameters (parental animals):

not examined

Litter observations:

OFFSPRING:
- Body weight: day 0, 4, 7 and 14 of lactation (litter weight by sex) and on day 21 (individual weights)
- External examination on day 0, 4, 7, 14 and 21 of lactation

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Gross necropsy of dams and pups on day 21 of lactation
- Histopathology on tissues of pups of control and high dose group

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals after mating
- Maternal animals: All surviving animals on lactation day 21

GROSS NECROPSY
- Gross necropsy of P females, of F1 generation: all animals, tissues were obtained from 9-10 animals/sex/level (Internal cavities (abdominal, thoracic, cranial, and scrotal) organs were removed and examined

HISTOPATHOLOGY / ORGAN WEIGHTS
Tissues from control and high level animals were examined microscopically.

Postmortem examinations (offspring):

see above

Statistics:

- Dunnett's Multiple Comparison Test, Mann-Whitney Test, with with Bonferroni Inequality Procedure, Fisher’s Exact Test with Bonferroni Inequality Procedure, (partially uncorrected) chi-square Test

Reproductive indices:

copulation, fertility and pregnancy indices

Offspring viability indices:

not calculated

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

incidentally fur discolouration and focal hair loss (not treatment-related)

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

In males during the majority of the study, no significant effects in females

Food efficiency:

not examined

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

not specified

Ophthalmological findings:

not specified

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:

not specified

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

PATERNAL TOXIC EFFECTS BY DOSE LEVEL:
- Two males in the high dose group died (week 1 and first week of mating)
- Males in the high dose group had a significantly lower body weight during the majority of the study
- No significant differences appeared in mating and fertility parameters
- Maternal mortality: none
- Body weight: no treatment related effects
- Clinical signs: incidentally fur discolouration and focal hair loss (not treatment-related)
- Mating success: 23/25, 25/25, 23/25 and 25/25 at 0, 20, 100 and 500 mg/m3, respectively
- Number pregnant per dose level: 21, 19, 17 and 19 at 0, 20, 100 and 500 mg/m3, respectively
- Gestational length: 22-23 days
- Gross pathology incidence and severity: no treatment related effects
- The number of corpora lutea, implantations and resorptions was not affected by treatment

Key result

Dose descriptor:

NOAEC

Remarks:

(highest concentration tested)

Effect level:

500 mg/m³ air

Sex:

male/female

Basis for effect level:

other: No significant effects on mating or fertility parameters

Key result

Critical effects observed:

no

Clinical signs:

not specified

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

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

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

- Mean litter size (day 0): 14, 13, 14 and 14 at 0, 20, 100 and 500 mg/m3, respectively
- Mean litter size (day 21): 8, 8, 8 and 8 at 0, 20, 100 and 500 mg/m3, respectively
- Sex ratio: no treatment related effects
- Body weight (day 0): 6.3, 6.6, 6.5 and 6.2 g at 0, 20, 100 and 500 mg/m3, respectively
- Body weight (day 21): 55, 58, 57 and 56 g at 0, 20, 100 and 500 mg/m3, respectively
- External abnormalities: none
- Histopathology: no treatment related effects

Key result

Dose descriptor:

NOAEC

Remarks:

(direct exposure: P-generation / indirect (intrauterine) exposure: embryos/foetus)

Generation:

F1

Effect level:

500 mg/m³ air

Sex:

male/female

Basis for effect level:

other: based on neonatal and perinatal mortality and body weight

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Conclusions:

No effects on mating or fertility parameters were observed in Sprague-Dawley rats after exposure to an aerosol of isopropylamine at analytical concentrations up to 499 mg/m3, resulting in a NOAEL of 499 mg/m3.

Executive summary:

In the fertility and reproduction studies, four groups of 20 male and 25 female rats each were exposed for 6 hrs/day, 5 days/wk (except holidays) for approximately 10.5 weeks. Each exposed male was then consecutively cohoused (1:1) with two unexposed females; exposed females were cohoused (1:1) with unexposed males. Treated males and females were exposed during the mating period (5 days/wk). Once mating occurred, treated females were exposed 7 days/wk through gestation day 20. Untreated female mates of exposed males were terminated approximately two weeks after copulation to assess fertility. Exposed females were housed in delivery boxes and delivered their pups. Pups were weaned on lactation Day 21 and necropsied. Mean analytical exposure concentrations were 20, 100, and 499 mg/3 in air. The mean body weight of exposed high level males was significantly reduced throughout most of the study. There were no treatment-related effects on mating, fertility, or reproduction parameters in exposed males or females. No gross or microscopic pathology changes were noted in FO or F1 animals.

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

500 mg/m³

Study duration:

subchronic

Species:

rat

Quality of whole database:

Valid one generation GLP study

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In a male fertility and female reproduction studies, four groups of 20 male and 25 female rats each were exposed for 6 hrs/day, 5 days/wk for approximately 10.5 weeks to vapors of monoisopropylamine (Heydens and Thake 1988). Each exposed male was then consecutively cohoused (1:1) with two unexposed females; exposed females were cohoused (1:1) with unexposed males. Treated males and females were exposed during the mating period (5 days/wk). Once mating occurred, treated females were exposed 7 days/wk through gestation day 20. Untreated female mates of exposed males were terminated approximately two weeks after copulation to assess fertility. Exposed females were housed in delivery boxes and delivered their pups. Pups were weaned on lactation Day 21 and necropsied. Mean analytical exposure concentrations were 20, 100, and 499 mg/m3. The mean body weight of exposed high level males was significantly reduced throughout most of the study.

There were no treatment-related effects on mating, fertility, or reproduction parameters in exposed males or females. No gross or microscopic pathology changes were noted in FO or F1 animals. The NOAEC was therefore 500 mg/m³ in this study.

Effects on developmental toxicity

Description of key information

In the offspring of rats exposed at up to 1000 mg/m³ during gestation days 6-15, no adverse developmental or teratogenic effects were observed after intrauterine exposure to isopropylamine.

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:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

note: not mentioned in ACC IUC5

Deviations:

yes

Remarks:

Food consumption was not measured, while a deviation from standard reproductive toxicity testing, considered an acceptable deviation.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

- Age (males): 10 weeks
- Weight at day 0 of gestation (females): 214-282 g
- Weight at day 0 of gestation (males): 317-389 g
- Number of animals: 25 females/group
- Thirty air changes per hour

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

air

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Method: Gas analyser
- Sampling time: at least 5 times/day (treatment); the control was checked for the presence of test material
twice during the study

Details on mating procedure:

- Mating: 1 female / 1 male
- Day 0 of gestation: presence of vaginal plug

Duration of treatment / exposure:

- Gestation days 6-15

Frequency of treatment:

- Six hours per day

Duration of test:

- Twenty days, Cesarean section on gestation day 20

Dose / conc.:

50 mg/m³ air (analytical)

Dose / conc.:

499 mg/m³ air (analytical)

Dose / conc.:

1 000 mg/m³ air (analytical)

No. of animals per sex per dose:

25 mated females per group

Control animals:

yes

Maternal examinations:

- Mortality: twice daily
- Clinical observations: on gestation days 0 and 6-20 (on treatment days after exposure)
- Body weight gain: gestation days 0, 6, 10, 13, 16 and 20
- Food consumption: not measured

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Macroscopy: findings dams recorded
- Microscopy: not performed

Ovaries and uterine content:

- Examination of uterine content: number of corpora lutea; relative position and number of live and dead foetuses and early and late resorptions

Fetal examinations:

- Examination of fetuses: sex; weight; external, visceral (1/2 of each litter) and skeletal (1/2 of each litter) findings

Statistics:

- Dunnett's test; Mann-Whitney U test; Fisher's Exact test

Indices:

not calculated

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Clinical signs of rales, labored breathing and vaginal discharge (one female) were uniquely observed in the high exposure level maternal animals. Sneezing was observed in both the high and mid exposure groups with higher incidence in the high exposure group. Fur staining/encrustation/nasal discharge was obsened at a higher incidence in the high exposure group maternal animals than the other exposure groups or the control group. During exposure, clear nasal discharge was observed in the high exposure group and sneezing was observed in the high exposure group
Low incidence of nasal discharge and sneezing were observed in the mid dose group.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

High exposure level: Mean maternal body weights were significantly lower than control values (about 14% lower on gestation day 20) and body weight loss or lower weight gains were observed for the periods of gestation days 6-10, 10-13, 13-16 and 6-20.
Mid exposure level: Reduced body weight gain for gestation days 6-10 and the overall period of gestation days 6-20. Absolute maternal body weights of mid exposure group animals were not significantly lower than control group values.

Food consumption and compound intake (if feeding study):

not examined

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:

not examined

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Reduced abdominal fat was observed in 9 high exposure level and 2 mid exposure level animals
Incidental hydronephosis, kidney stones and dilated ureter were observed without relationship to treatment.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

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:

effects observed, non-treatment-related

Description (incidence and severity):

Early resorption and consequently postimplantation loss were slightly elevated above control values in the mid exposure
group (mean of l.O/dam vs. 0.6/dam); the difference was not statistically significant at the 5% confidence level with the
Bonferroni inequality. Early resorption for the high and low exposure groups were not statistically different from the control
value

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Key result

Dose descriptor:

NOAEC

Effect level:

500 mg/m³ air

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

NOEC

Effect level:

50 mg/m³ air

Basis for effect level:

other: maternal toxicity

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

other: unspecific signs of toxicity

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

One malformation finding, bent limb bones, was observed in a single fetus in the high exposure group and eight fetuses from this litter exhibited bent rib variation findings. The malformation and variation findings observed in this litter are considered to be the result of factors unique to the dam that were not related to exposure. The fact that the dam of this litter uniquely exhibited a large body weight loss on gestation days 13-16 supports this conclusion. On a litter basis no significant increase in bent rib findings were observed and the increased number of fetuses with bent ribs in the high exposure group because of multiple findings in a single litter is not considered to be evidence for a treatment related effect.
An elevation in reduced 13th rib ossification was observed for the high exposure group, but the difference was not statistically different from the control group with the Bonferroni inequality applied and no supportive treatment related growth retardation findings such as reduced fetal weight or other reduced ossification findings were observed. For these reasons the elevation in reduced 13th rib ossification in the high exposure group was concluded not to be treatment related.

Visceral malformations:

no effects observed

Other effects:

no effects observed

Key result

Dose descriptor:

NOAEC

Effect level:

1 000 mg/m³ air

Basis for effect level:

other: teratogenicity

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

no

Conclusions:

Under the conditions of this study, there was no developmental toxicity observable in rats, even at maternal toxic levels

Executive summary:

Groups of 25 mated female Sprague-Dawley rats were exposed to target isopropylamine concentrations of 50, 500, or 1000 mg/m3 by inhalation, six hours per day, on days 6-15 of gestation. A concurrent control group received house-conditioned air only. Dams were sacrificed on gestation day 20, implantations were described, and fetuses were removed from the uterus. Fetuses underwent a gross external examination and were processed for subsequent visceral or skeletal examination. Analytically measured study mean exposure levels and standard deviations were 50 +/- 1, 499 +/- 5 and 1000 +/- 8 mg/m3 for the low, mid and high exposure levels. No spontaneous deaths occurred in any of the exposure groups or the control group. There were clear signs of maternal toxicity at the high exposure level. Mean maternal body weights were significantly lower than control values (about 14% lower on gestation day 20) and body weight loss or lower weight gains were observed for the periods of gestation days 6-10, 10-13, 13-16 and 6-20. Rales, labored breathing and vaginal discharge (one female) were uniquely observed clinical signs in high exposure group females. Treatment related clinical signs of nasal discharge, sneezing and fur staining/encrustation were also observed in high exposure group females. Slight toxicity was observed at the mid exposure level as evidenced by reduced body weight gain for gestation days 6-10 and the overall period of gestation days 6-20. Absolute maternal body weights of mid exposure group animals were not significantly lower than control group values. Low incidence of nasal discharge and sneezing were observed in the mid dose group. There was no apparent maternal toxicity at the low exposure level. The only maternal postmortem findings that were considered treatment related were observations of reduced abdominal fat in 9 high exposure level and 2 mid exposure level animals.There were no clear indications of embryotoxicity or fetotoxicity at any of the exposure levels. Pregnancy rates, numbers of fetuses and preimplantation loss were comparable between all exposure groups and the control group. Increased mean early resorptions/dam above the control value (less than two fold) in the mid exposure group were not considered to be treatment related because of lack of statistical significance with the Bonferroni inequality and lack of a dose response pattern. Fetal weights and sex distributions were comparable between all treatment groups and the control group. Morphological malformation findings were confined to sporadic incidence in a few fetuses and litters. No statistically significant malformation increases or dose response patterns were observed. One malformation finding, bent limb bones, was observed in a single fetus in the high exposure group and eight fetuses from this litter exhibited bent rib variation findings. The malformation and variation findings observed in this litter are considered to be the result of factors unique to the dam that were not related to exposure. The fact that the dam of this litter uniquely exhibited a large body weight loss on gestation days 13-16 supports this conclusion. On a litter basis no significant increase in bent rib findings were observed and the increased number of fetuses with bent ribs in the high exposure group because of multiple findings in a single litter is not considered to be evidence for a treatment related effect. An elevation in reduced 13th rib ossification was observed for the high exposure group, but the difference was not statistically different from the control group with the Bonferroni inequality applied and no supportive treatment related growth retardation findings such as reduced fetal weight or other reduced ossification findings were observed. For these reasons the elevation in reduced 13th rib ossification in the high exposure group was concluded not to be treatment related.

In conclusion, treatment of Sprague-Dawley rats by the inhalation exposure route at mean analytical levels of 50, 499 or 1000 mg/m3 during the period of major organogenesis did not induce embryotoxic, fetotoxic or teratogenic effects, although slight maternal toxicity was observed at the 499 mg/m3 exposure level and substantial maternal toxicity was observed at the 1000 mg/m3 level.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

1 000 mg/m³

Study duration:

subacute

Species:

rat

Quality of whole database:

Valid GLP guideline inhalation study

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In a study conducted in a manner quivalent or similar to OECD Guideline 414 (Prenatal Developmental Toxicity Study), groups of 25 female Sprague-Dawley rats were exposed by whole body vapor inhalation to isopropylamine at 50, 500 or 1000 mg/m³ on gestation days 6-15 (Kier and Thake, 1988). Embryonal and fetal development was not impaired following inhalation exposure of pregnant rats to high levels of isopropylamine. Maternal toxicity was observed at 1000 mg/m³, based on effects on bodyweight, treatment-related clinical signs (nasal discharge, rales, labored breathing, sneezing and fur staining/encrustation) and macroscopically observed reduced abdominal fat. The NOAEC (maternal) was 500 mg/m³, and the NOAEC (offspring) was 1000 mg/m^3.

Mode of Action Analysis / Human Relevance Framework

In the absence of information on a species specific mode of action the information obtained in the in vitro studies are regarded as relevant for humans.

Justification for classification or non-classification

Based on the negative findings on developmental toxicity and fertility in two studies in rats it is concluded that isopropylamine has not to be classified for reproductive toxicity according to Regulation (EC) No 1272/2008.