Morpholine, 4-C12-14-alkyl derivs.

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented and cited in the peer-reviewed regulatory agency.

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

not applicable

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Crj:CD(SD)IGS

Sex:

male/female

Details on test animals or test system and environmental conditions:

Four weeks old Crj:CD(SD)IGS rats bought from Charles River Japan, Inc. They were put in quarantine and acclimatization for 7 d before use.

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

The test solution was prepared and diluted to dosing concentrations by injection solvent every week. They were kept in a refrigerator. The diluted solution was also confirmed to be stable for 8 d.

Duration of treatment / exposure:

Males: 42 d
Females: From 14 d before mating to Day 3 of lactation

Frequency of treatment:

Once daily

Remarks:

Doses / Concentrations:
0 (vehicle), 50, 150, 500 mg/kg bw/day
Basis:
nominal conc.

No. of animals per sex per dose:

13/sex/dose

Control animals:

yes, concurrent vehicle

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes

Oestrous cyclicity (parental animals):

Yes

Sperm parameters (parental animals):

Parameters examined in P male parental generations: Testis weight, epididymis weight, histopathological examination of reproductive organs

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring: Number and sex of pups, stillbirths, live births, viability index

Postmortem examinations (parental animals):

Terminal killing: Males at Day 43; females at Day 4 of lactation.

Postmortem examinations (offspring):

Necropsy was perfomed.

Statistics:

Statistical analysis of offspring was carried out using the litter as the experimental unit. Bartlett's test of homogeneity of variance was used to determine if the groups had equivalent at the 5% level of significance. If variance was equivalent, the groups were compared by one-way analysis of variance. If significant
differences were found, Dunnett's test was performed. If the groups did not have equivalent variances, the Kruskal-Wallis test was used to assess the overall effects. Whenever significant differences were noted, Dunnett-type test was performed. Mann-Whitney U-test or Fisher's exact test was also used.

Reproductive indices:

Copulation index and fertility index

Offspring viability indices:

Gestation index , implantation index, delivery index , birth index , live birth index , sex ratio and viability index

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

No deaths were found in males of any group. One female at 500 mg/kg bw/day showed tremor and died on Day 2 of lactation. In clinical signs, salivation was observed in males and females at 150 mg/kg bw/day and higher. Decrease in body weight gain and food consumption were detected in male at 500 mg/kg bw/day and females at 150 mg/kg bw/day and higher. Absolute and relative weights of testes and epididymides were not affected by dosing. Necropsy and histopathological examination of reproductive organs revealed no abnormalities related to dosing. No adverse effects on estrous cycle, copulation, fertility, gestation length, gestation index or number of corpora lutea were found. No significant changes were observed in numbers of implantations, pups live pups and in indexes for implantation, delivery, birth and live birth were detected.

Dose descriptor:

NOAEL

Remarks:

(for reproductive toxicity)

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Dose descriptor:

NOAEL

Remarks:

(for systemic toxicity)

Effect level:

150 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Based on observed clinical signs such as salivation as well as decrease in body weight and food consumption at higher doses.

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Gross pathological findings:

no effects observed

There were no treatment-related changes in the body weight external appearance, general conditions or necropsy findings in offspring of rats.

Reproductive effects observed:

not specified

Table 1. Body weight changes of rats treated orally with N-ethylmorpholine in preliminary reproduction toxicity screening test:

Dose (mg/kg/ bw/day)	0	50	150	500
Male No. of animals	13	13	13	13
Terminal body weight (g) +/-S.D.	497.0     40.4	494.0     30.9	488.0     38.9	457.5* 31.7
Female No. of animals	13	13	13	13
Days 14 of administration (g) +/-S.D.	266.5     13.1	263.6     15.7	263.4     17.8	259.5 17.5
No. of animals	12	12	12	12
Days 20 of pregnancy (g) +/-S.D.	428.5     33.1	423.2     29.8	410.6     27.2	386.1*   42.1
No. of animals	12	12	12	12
Days 4 of lactation (g) +/-S.D.	345.6     22.8	338.4 26.9	330.1 19.3	329.7 24.5

Significant difference from control group; *p=<0.05,**p=<0.01

Table 2. Food consumption of rats treated orally with N-ethylmorpholine in preliminary reproduction toxicity screening test

Dose (mg/kg/ bw/day)	0	50	150	500
Male No. of animals	13	13	13	13
Days of administration (g)
1-2 +/-S.D.	27.8        1.9	26.9 2.3	25.4 3.7	21.3** 2.7
7-8 +/-S.D.	25.1 1.9	25.8 1.5	25.3 2.8	22.1** 1.7
14-15     +/-S.D.	27.1 2.9	27.7 8.2	26.6 2.9	24.3* 3.2
29-30 +/-S.D.	28.7 2.4	29.5 2.1	28.0 2.7	24.2** 1.7
35-36 +/-S.D.	29.9 7.5	26.7 3.3	27.7 3.0	27.2 6.4
41-42     +/-S.D.	29.6        3.3	29.4 3.4	28.9 4.1	26.2* 2.0
Female No. of animals	13	13	13	13
Days of administration (g)
1-2 +/-S.D.	20.7 1.9	18.5 3.5	16.6** 3.4	16.5** 3.7
7-8          +/-S.D.	19.7 3.7	19.4 3.9	20.2 2.9	19.9 3.5
14-15 +/-S.D.	19.9 3.7	20.4 2.6	19.7 2.3	19.4 1.8
No. of animals	12	12	12	12
Days of pregnancy (g)
0-1 +/-S.D.	21.0        2.6	21.1 1.9	19.4 2.7	18.4* 2.9
7-8          +/-S.D.	28.9 3.6	28.5 3.0	25.5* 3.4	23.2** 3.2
14-15     +/-S.D.	28.6 3.4	26.8 2.8	26.3 2.0	24.7* 4.3
20-21     +/-S.D.	19.3 3.5	21.0 2.4	20.8 4.0	18.7 2.5
No. of animals	12	12	12	9
Days 4 of lactation (g)
3-4 +/-S.D.	47.1 6.7	49.4 4.6	43.3 4.3	41.4        8.8

Significant difference from control group; *p=<0.05,**p=<0.01

Table 3. Estrous cycle and reproductive performance in rats treated orally with N-ethylmorpholine in preliminary reproduction toxicity screening test

Dose (mg/kg/ bw/day)	0		50	150	500
Estrous cycle
Type of cycle during treatment period
4-day cycle		13	13	12	12
4,5-day cycle		0	0	1	1
Length of estrous cycle in days +/-S.D.		4.0 0.0	4.0 0.0	4.0 0.1	4.0 0.1
Reproductive performance
Number of mated pairs		13	13	13	13
Number of copulated pairs		13	13	12	12
Copulation index (%)		100.0	100.0	92.3	92.3
Number of pregnant animals		12	12	12	11
Fertility index (%)		92.3	92.3	100.0	91.7
Pairing days until copulation  +/-S.D.		2.3 1.1	2.2 1.1	3.3 1.7	2.6 1.3
Frequency of vaginal estrus  +/-S.D.		1.0 0.0	1.0 0.0	1.1 0.3	1.0 0.0

Copulation index = (Number of copulated pairs/Number of mated pairs) X 100
Fertility index = (Number of pregnant animals/Number of copulated pairs) X 100

Table 4. Summary of development of pups from dams treated orally with N-ethylmorpholine in preliminary reproduction toxicity screening test

Dose (mg/kg/ bw/day)	0	50	150	500
Number of pregnant females	12	12	12	11
Gestation index (%)	100.0	100.0	100.0	90.9
Gestation length in days +/-S.D.	22.7 0.5	22.3 0.7	22.3 0.5	22.8 0.6
Number of corpora lutea +/-S.D.	16.2 2.0	16.9 1.8	15.7 1.9	16.0 3.0
Number of implantation sites +/-S.D.	15.6 2.6	16.1 1.7	14.8 1.8	13.1 4.7
Implantation index (%) +/-S.D.	95.9 7.4	95.2 4.9	94.9 6.1	80.6 26.6
Day 0 of lactation
Number of pups born +/-S.D.	14.2        2.8	15.1 1.2	13.8 1.6	11.4 4.9
Delivery index (%) +/-S.D.	90.6 9.3	94.1 6.0	93.1 7.7	84.6 15.8
Number of pups alive +/-S.D.	13.7 2.9	15.0 1.3	13.7 1.7	10.0 5.4
Birth index (%) +/-S.D.	87.4 9.7	93.6 5.7	92.5 8.0	71.2 32.7
Live birth index (%) +/-S.D.	96.5 5.6	99.4 1.9	99.4 2.2	83.5 35.6
Sex ratio on day 0 (%) +/-S.D.	52.4 13.2	47.9 8.0	48.9 12.6	54.2 26.3
Day 4 of lactation
Number of pups alive +/-S.D.	13.6 2.8	15.0 1.3	13.5 1.7	11.6 3.9
Viability index (%) +/-S.D.	99.5 1.7	100.0 0.0	98.8 2.8	98.1 3.8
Sex ratio on day 4 (%) +/-S.D.	52.6 13.1	47.9 8.0	49.5 12.6	58.5 25.9

Gestation index = (Number of females with live pups/ Number of pregnant females) X 100
Implantation index = (Number of implantation sites/ Number of corpora lutea) X 100
Delivery index = (Number of pups born/Number of implantation sites) X 100
Birth index = (Number of live pups on day 0/Number of implantation sites) X 100
Live birth index = (Number of live pups on day 0/Number of pups born) X 100
Sex ratio = (Number of male live pups/Number of female live pups) X 100
Viability index = (Number of live pups on day 4/Number of live pups on day 0)

Conclusions:

Based on the absence of any adverse effects of the read-across substance, ethylmorpholine on reproductive and developmental parameter, the NOAEL for reproductive and developmental toxicity is considered to be 500 mg/kg bw/day. Further, based on clinical signs and decreased body weight gain and food consumption, the LOAEL and NOAEL for general toxicity in parent animals are considered to be 150 and 50 mg/kg bw/day, respectively.

Executive summary:

The toxicity to reproduction of the read-across substance, 4-ethylmorpholine was tested in a reproduction / developmental toxicity screening test according to the OECD Guideline 421 in compliance with GLP.

Drj:CD(SD)IGD rats (13 animals/sex/dose) were given test substance by gavage at 0 (vehicle: water), 50, 150 or 500 mg/kg bw/day. Males were dosed for a total of 42 d beginning 14 d before mating. Females were dosed from 14 d before mating to Day 3 of lactation throughout the mating and pregnancy period.

No deaths were found in males of any group. One female at 500 mg/kg bw/day died on Day 2 of lactation. Tremor was observed in the female which died, and transient salivation after dosing was observed in males and females at 150 mg/kg bw/day and higher. Decrease in body weight gain accompanied by reduced food consumption was detected in males at 500 mg/kg bw/day and females at 150 mg/kg bw/day and higher. Body weight gains on Days 1-7, Days 21 -28 and Days 35-43 of administration in males at 500 mg/kg bw/day, on Days 1-7 of administration, Days 7-14 and Days 14-21 of pregnancy and Days 0-4 of lactation in females at 500 mg/kg bw/day, and Days 1-7 of administration, Days 0-7 of pregnancy and Days 0-4 of lactation in females at 150 mg/kg bw/day were found. Absolute and relative weights of the testes and epididymides in the groups treated with this chemical were not different from the control group. Necropsy and histopathological examinations revealed no changes related to the administration of this chemical. Histopathological examinations of the testes, epididymides and ovaries revealed no toxicological changes. There were no adverse effects on estrous cyclicity, copulation index, fertility index, precoital interval, gestation length, gestation index or number of corpora lutea. No significant changes were observed in numbers of implantations and pups and live pups, and in indexes for implantation, delivery, birth and live birth. There were no treatment- related changes in body weight, external appearance or necropsy findings in offspring of rats.

Based on the absence of any adverse effects on reproductive and developmental parameter, the NOAEL for reproductive and developmental toxicity is considered to be 500 mg/kg bw/day. Further, based on clinical signs and decreased body weight gain and food consumption, the LOAEL and NOAEL for general toxicity in parent animals are considered to be 150 and 50 mg/kg bw/day, respectively.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Reliable guideline-compliant study cited in a publication, based on read-across.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Available 90-day study on C12-14 alkylmorpholine did not indicate effects to the reproductive organs, and also a developmental toxicity study (OECD 414) showed no effects on reproductive parameters at highest dose tested.

 

The toxicity to reproduction of the read-across substance, 4-ethylmorpholine was tested in a reproduction / developmental toxicity screening test according to the OECD Guideline 421 in compliance with GLP. Information in support of cross-reading is attached to section 7.1 toxicokinetics, in which molecular profiling, available data and results from QSARs are listed.

Estimation of possible metabolism indicates a similar profile for C12-14 alkylmorpholine and ethylmorpholine.

 

Drj:CD(SD)IGD rats (13 animals/sex/dose) were given test substance by gavage at 0 (vehicle: water), 50, 150 or 500 mg/kg bw/day. Males were dosed for a total of 42 d beginning 14 d before mating. Females were dosed from 14 days before mating to Day 3 of lactation throughout the mating and pregnancy period.

No deaths were found in males of any group. One female at 500 mg/kg bw/day died on Day 2 of lactation. Tremor was observed in the female that died, and transient salivation after dosing was observed in males and females at 150 mg/kg bw/day and higher. Decrease in body weight gain accompanied by reduced food consumption was detected in males at 500 mg/kg bw/day and females at 150 mg/kg bw/day and higher. Absolute and relative weights of the testes and epididymides in the groups treated with this chemical were not different from the control group. Necropsy and histopathological examinations revealed no changes related to the administration of this chemical. Histopathological examinations of the testes, epididymides and ovaries revealed no toxicological changes. There were no adverse effects on estrous cyclicity, copulation index, fertility index, precoital interval, gestation length, gestation index or number of corpora lutea. No significant changes were observed in numbers of implantations and pups and live pups, and in indexes for implantation, delivery, birth and live birth. There were no treatment- related changes in body weight, external appearance or necropsy findings in offspring of rats. Based on the absence of any adverse effects on reproductive and developmental parameter, the NOAEL for reproductive and developmental toxicity is considered to be 500 mg/kg bw/day. Further, based on clinical signs and decreased body weight gain and food consumption, the LOAEL and NOAEL for general toxicity in parent animals are considered to be 150 and 50 mg/kg bw/day, respectively.

 

In conclusion:

No indication of effects on reproductive organs in 90-day repeated dose study and no effects in reproductive parameters in a developmental (OECD 414) study at highest dose levels tested. Also cross-reading to reproduction screening (OECD 421) study with a structurally related ethyl morpholine showed no effects on reproduction.

Further considering that local effects have shown to be the most critical, and that use only involves industrial applications, the risk of possible reproductive effects from repeated exposures can be considered very limited. Further studies for the evaluation of the possible hazards for reproduction are therefore not indicated.

Short description of key information:
No indication of effects on reproductive organs in 90-day repeated dose study on C12-14 alkylmorpholine and no effects in reproductive parameters in a developmental (OECD 414) study at highest dose levels tested. Also cross-reading to reproduction screening (OECD 421) study with a structurally related ethyl morpholine showed no concerns.

Justification for selection of Effect on fertility via oral route:
Only study available.

Effects on developmental toxicity

Description of key information

Prenatal developmental toxicity study of C12-14-alkylmorpholine in rat resulted to a maternal NOAEL of 30 mg/kg based on mortality, effects on body weight gain and macroscopic findings (local irritant effects) at 100 mg/kg bw/day. Developmental NOAEL > 100 mg/kg, being the highest dose tested.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 June 2015 - 09 July 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to OECD/EC guidelines and GLP prinicples.

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

January 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.31 (Prenatal Developmental Toxicity Study)

Version / remarks:

May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

Version / remarks:

August 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

dd 3 November 2015

Limit test:

no

Species:

rat

Strain:

other: RccHan:WIST

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories B.V., Venray, The Netherlands
- Age at study initiation: 10-14 weeks
- Weight at study initiation: 187-285g
- Fasting period before study: No
- Housing: Individual housing in Macrolon cages (MIII type)
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SNIFF®Spezialdiäten GMBH, Soest, Germany)
- Water: Free access to tap water
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.0-21.6
- Humidity (%): 47-78
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 21 June 2015 To: - 09 July 2015

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Formulations were prepared daily within 6 hours prior to dosing and were homogenized to a visually acceptable level. Adjustment was made for specific gravity of the test substance (0.87) and vehicle (0.92). No correction was made for the purity/ composition of the test substance.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Based on trial formulations at testing facility and on information provided by the sponsor.
- Amount of vehicle (if gavage): 5 mL/ kg body weight

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were conducted on a single occasion during the treatment phase, according to a validated method. Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations).
The accuracy of preparation was considered acceptable if the mean measured concentrations were 90-110% of the target concentration. Homogeneity was demonstrated if the coefficient of varation was ≤10%.

Details on mating procedure:

- Impregnation procedure: purchased timed pregnant (proof: vaginal plug (day 0 of gestation))

Duration of treatment / exposure:

15 days (days 6 to 20 post coitum, inclusive)

Frequency of treatment:

once daily

Duration of test:

until day 21 post-coitum

Remarks:

Doses / Concentrations:
0, 10, 30, 100 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

22 (females only, main study);
9 (females only, dose range finding study)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were selected based on results of dose range finding study (details below).
- Assignment rationale: randomized by body weight, females mated on the same day in the same subgroup.

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once daily from day 1 post coitum up to the day prior to necropsy

BODY WEIGHT: Yes
- Time schedule for examinations: days 1, 3, 6, 9, 12, 15, 18 and 21 post coitum

FOOD CONSUMPTION :
- Time schedule: days 1-3, 3-6, 6-9, 9-12, 12-15, 15-18 and 18-21 post coitum

WATER CONSUMPTION: Yes
- Subjective appraisal was maintained during the study (no quantitative investigation as no treatment related effect was expected)

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21 post coitum
- External, thoracic and abdominal examination

OTHER:
Each ovary and uterine horn of animals surviving to planned necropsy was dissected and examined throughfully.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: weight of each fetus, sex of each fetus from the ano-genital distance and also from gonadal inspections and externally visible macroscopic fetal abnormalities

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter (incl. confirmation of sex by internal examination)

Statistics:

The following statistical methods were used to analyze the data:
- If the variables could be assumed to follow a normal distribution, the Dunnett-test (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
- The Steel-test (many-to-one rank test) was applied if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test was applied to frequency data.
- The Mann Whitney test was used to compare mean litter proportions (percent of litter) of the number of viable and dead fetuses, early and late resorptions, total resorptions, pre- and post-implantation loss, and sex distribution.
- Mean litter proportions (percent per litter) of total fetal malformations and developmental variations (external, visceral and skeletal) and each particular external, visceral and skeletal malformation or variation were subjected to the Kruskal-Wallis nonparametric ANOVA test to determine intergroup differences. If the ANOVA revealed statistically significant (p<0.05) intergroup variance, Dunn's test was used to compare the compound-treated groups to the control group.

All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance. Group means were calculated for continuous data and medians were calculated for discrete data (scores). Test statistics were calculated on the basis of exact values for means and pooled variances. Individual values, means and standard deviations may have been rounded off. Therefore, two groups may display the same printed means for a given parameter, yet display different test statistics values.
No statistics were applied for data on maternal survival, pregnancy status, group mean numbers of dead fetuses, early and late resorptions, and pre and post-implantation loss.

Indices:

Pre-implantation loss (%) = ((number of corpora lutea – number of implantation sites)/ number of corpora lutea) X 100;
Post-implantation loss (%) = ((number of implantation sites – number of live fetuses)/ number of implantation sites) X 100;
Viable fetuses affected/ litter (%) = ((number of viable fetuses affected/litter)/ (number of viable fetuses/litter)) x 100

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
One rat treated at 100 mg/kg bw/day was killed in extremis on day 20 post coitum, after a rapidly declining health status from day 19 post coitum onwards (incl. clinical signs like hunched posture on day 15 post coitum). No further mortality occurred at any dose level. No clinical signs were noted amongst surviving rats that were considered related to the treatment (only incidental observations). Body weight gain (with and without correction for uterus weight) appeared slightly lower in rats treated at 100 mg/kg bw/day compared to controls (35% vs 41% body weight gain in controls (absolute), 6.5% vs 9.6% body weight gain in controls (with correction for uterus weight)), this was primarily related to three animals with marked body weight loss (not statistically significant). Relative food consumption was reduced on day 21 post coitum for rats dosed at 100 mg/kg bw/day, which was merely caused by the three rats that suffered weight loss. Body weight gain with and without correction for uterus weight at 10 and 30 mg/kg bw/day was unaffected by the treatment, food consumption (absolute and relative) in these groups was similar to control group. Macroscopic examination revealed effects in females treated at 100 mg/kg bw/day. The female killed in extremis showed black-brown foci on the glandular stomach with irregular surface of the forestomach, enlarged and dark-red discoloured adrenal glands, and a reduced size of the thymus. Irregular surface of the stomach was also recorded for 3 additional females in this group, with one of these females showing black-brown foci on the glandular mucosa of the stomach. Another female in this group showed yellowish contents of the gastro-intestinal tract, a thickened duodenal wall with gelatinous contents, black-brown foci on the ileum with gelatinous contents and reduced size of the spleen. None of the animals in the other groups showed test substance related macroscopic effects.

There were no effects on the number of pregnant females, corpora lutea, implantation sites or pre- or post-implantation loss noted up to 100 mg/kg bw/day, a summary of the outcome is included in tabular form.
Examination of cage debris of pregnant females revealed ni signs of abortion or premature birth.

Dose descriptor:

NOAEL

Effect level:

>= 30 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Dose descriptor:

NOAEL

Effect level:

>= 100 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
There were no treatment-related effects on litter size for any group. Overview in tabular format of the results is included below. Mean litter sizes were 11.1, 11.0, 10.9 and 10.5 fetuses/litter for respectively the control, 10, 30 and 100 mg/kg bw/day groups. The male:female sex ratio and fetal body weight was unaffected by the treatment up to and including 100 mg/kg bw/day.
Three fetuses at 100 mg/kg bw/day and one at 30 mg/kg bw/day were external malformed, which consisted at 100 mg/kg bw/day of a hind limb rotated inwards (no skeletal cause found), a small lower jaw and cleft palate and a fetus with a small tail (only three caudal vertebrae present). At 30 mg/kg bw/day, one fetus had a meningocele (skeletally confirmed). Because of the single occurrences and diverse nature of these abnormalities, they were not considered treatment related.
Visceral malformations were found in one control, one fetus at 30 mg/kg bw/day and in 4 fetuses (in 4 litters) at 100 mg/kg bw/day. Two fetuses at 100 mg/kg bw/day and one control fetus had external hydrocephaly. One fetus at high dose had a small eye and internal hydrocephaly. The fourth affected fetus at high dose had a retroesophageal aortic arch. The affected fetus at 30 mg/kg bw/day was found to have situs inversus. Due to the incidental nature and previous observation of these malformations in historical control fetuses, these malformations were not considered adverse.
Distended urinary bladder and absent and/or small renal papillae occurred in 2 high dose litters at respectively 7.0% and 6.2% (in historical controls these variations occurred at respectively 0.0% and 0.2%). These findings occurred in the two litters with lowest mean fetal body weights, and marked body weight loss was recorded for both dams, suggesting influence of maternal toxicity rather than direct effect of the test substance. Other visceral variations were not considered to be treatment-related as they occurred in the absence of a dose-related incidence trend or were observed within the range of historical control data.
A statistically significant increase was attained for reduced ossification of vertebrae centra at 100 mg/kg bw/day. This variation was noted at a mean litter proportion of 0.0%, 0.0%, 2.0% and 5.9% per litter in respectively the control, 10, 30 and 100 mg/kg bw/day groups. The values at 30 and 100 mg/kg bw/day were also above the maximum historical value (1.6% per litter). The increase at 100 mg/kg bw/day was caused by 5 fetuses out of 5 litters, of which 3 fetuses had low body weights. Moreover, two of these had a vertebra anomaly as well. This variation was not considered adverse. Other skeletal variations were not considered treatment related as they occurred at frequencies that were within the range of historical control data or were observed in control fetuses only.
Skeletal malformations were noted in 1 (1), 4 (3), 1 (1) and 3 (3) fetuses (litters) in respectively the control, 10, 30 and 100 mg/kg bw/day groups. Two skeletally malformed fetuses at 100 mg/kg bw/day also had external end visceral abnormalities. One fetus additionally had fused sternebrae and bent limb bones, the other fetus also had a vertebral anomaly with associated rib anomaly and a sternal anomaly. The third skeletally malformed fetus in the high dose group had a malpositioned metatarsal. The skeletal malformations in these three fetuses occurred incidentally, therefore they were not considered treatment related. The only other skeletal malformation in this study (a rib without a head) was observed in a control fetus.
Overall it was concluded that there were no treatment-related external variations or malformations, skeletal malformations and visceral malformations. The observed visceral variations were considered to be related to maternal toxicity and rather a secondary effect to test substance exposure. The observed skeletal variation was not considered adverse.

Abnormalities:

not specified

Developmental effects observed:

not specified

Results dose range finding study:

Maternal effects:

At 600 mg/kg bw/day, one animal showed significant weight loss and was sacrificed in extremis. All other animals in this dose group showed clinical signs (hunched posture, piloerection, lethargy, slow breathing, faeces containing mucus and/or ptosis). Five remaining rats were sacrificed on day 20 post coitum (fetuses were not examined). Necropsy revealed irregular surface of the forestomach, and in the sacrificed animal emaciation and gelatinous contents of the gastro-intestinal tract.

At 300 mg/kg bw/day, one female was found dead on day 15 and two on day 20 post coitum, the remaining females were sacrificed in extremis on day 20 post coitum. Clinical signs of these rats included lethargy, hunched posture, piloerection, diarrhea, lean appearance, yellow mouth, wet/dirty genital region (urine) and/or low water intake). Mean body weight gain and food consumption were lower than controls throughout treatment. At necropsy, two females appeared emaciated. At 100 mg/kg bw/day, no mortality occurred. One female showed ptosis, and one female showed hunched posture, piloerection and lean appearance on days 19 and/or 20 post coitum. Body weight and food consumption appeared similar to controls. At 30 mg/kg bw/day, all animals survived until sacrifice, no clinical signs were noted. Body weight and food intake was normal.

Necropsy revealed irregular surface of the forestomach in all rats examined from group treated with 600 mg/kg bw/day (5/5), in 5/6 females at 300 mg/kg bw/day, in 2/6 females at 100 mg/kg bw/day and in 1/6 rats at 30 mg/kg bw/day.

Pregnancy/delivery/fetal findings:

Three early deliveries were recorded on day 21 post coitum for one female in different dose groups, which were considered unrelated to treatment. One control and one female at 100 mg/kg bw/day were found to be non-gravid. This was not considered related to treatment. The number of early resorptions appeared higher than controls at 100 mg/kg bw/day. Based on individual variations across the dose groups, this was considered unrelated to treatment. Up to 100 mg/kg bw/day, litter sizes were within normal limits, sex ratios were similar to controls, fetal body weights appeared unaffected by treatment, and all viable fetuses had no external abnormalities. Corpora lutea and implantation counts were normal up to 100 mg/kg bw/day. The incidence of pre- and post-implantation loss across the dose groups showed no relationship to treatment.

Results chemical analysis of formulations:

The concentrations analysed in the formulations of low, mid and high dose groups were in agreement with target concentrations (i.e. mean accuracies between 94% and 107%). No test substance was detected in the control group formulation. The formulations of low and high dose groups were homogeneous (i.e. coefficient of variation ≤ 1.9%).

Conclusions:

Prenatal developmental toxicity study of C12-14-alkylmorpholine in rat resulted to a maternal NOAEL of 30 mg/kg based on mortality, effects on body weight gain and macroscopic findings (local irritant effects) at 100 mg/kg bw/day. Developmental NOAEL > 100 mg/kg, being the highest dose tested.

Executive summary:

A prenatal developmental toxicity study was performed with C12-14-alkylmorpholine in rats according to OECD/EC guidelines and GLP principles. Pregnant rats (22/group) were exposed by oral gavage to 0, 10, 30 and 100 m/kg bw/day from day 6 to day 20 post coitum. Accuracy and homogeneity of formulations were confirmed by chemical analyses.

No maternal toxicity was observed at 10 and 30 mg/kg bw/day. At 100 mg/kg bw/day, one rat died on day 20 post coitum. It could not be excluded that this death was related to the test substance, since necropsy findings in the gastro-intestinal tract for this female resembled those seen for several other females in the high dose group and consisted of lesions in the stomach wall and black brown foci). At high dose, the average body weight gain was affected (not statistically significant, mainly caused by two surviving females with marked body weight loss). There were no treatment-related effects on litter size for any group. The male:female sex ratio and fetal body weight was unaffected by the treatment up to and including 100 mg/kg bw/day. Overall it was concluded that there were no treatment-related external variations or malformations, skeletal malformations and visceral malformations. The observed visceral variations were considered to be related to maternal toxicity and rather a secondary effect to test substance exposure. The observed skeletal variation was not considered adverse.

In conclusion, the maternal No Observed Adverse Effect Level (NOAEL) for C12-14-alkylmorpholine was established at 30 mg/kg bw/day based on mortality, effects on body weight gain and macroscopic findings (local irritant effects) at 100 mg/kg bw/day. A developmental NOAEL of at least 100 mg/kg was established, as no adverse effects on fetal development were seen at this level.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

GLP study with Klimisch score 1.

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

A prenatal developmental toxicity study was performed with C12-14-alkylmorpholine in rats according to OECD/EC guidelines and GLP principles. Pregnant rats (22/group) were exposed by oral gavage to 0, 10, 30 and 100 m/kg bw/day from day 6 to day 20 post coitum. Accuracy and homogeneity of formulations were confirmed by chemical analyses.

No maternal toxicity was observed at 10 and 30 mg/kg bw/day. At 100 mg/kg bw/day, one rat died on day 20 post coitum. It could not be excluded that this death was related to the test substance, since necropsy findings in the gastro-intestinal tract for this female resembled those seen for several other females in the high dose group and consisted of lesions in the stomach wall and black brown foci). At high dose, the average body weight gain was affected (not statistically significant, mainly caused by two surviving females with marked body weight loss). There were no treatment-related effects on litter size for any group. The male:female sex ratio and fetal body weight was unaffected by the treatment up to and including 100 mg/kg bw/day. Overall it was concluded that there were no treatment-related external variations or malformations, skeletal malformations and visceral malformations. The observed visceral variations were considered to be related to maternal toxicity and rather a secondary effect to test substance exposure. The observed skeletal variation was not considered adverse.

In conclusion, the maternal No Observed Adverse Effect Level (NOAEL) for C12-14-alkylmorpholine was established at 30 mg/kg bw/day based on mortality, effects on body weight gain and macroscopic findings (local irritant effects) at 100 mg/kg bw/day. A developmental NOAEL of at least 100 mg/kg was established, as no adverse effects on fetal development were seen at this level.

 

The lack of effects on reproduction is supported form cross-reading to a reproduction / developmental toxicity screening test (OECD 421) with 4-ethylmorpholine. Information in support of cross-reading is attached to section 7.1 toxicokinetics, in which molecular profiling, estimation of possible metabolism, available data and results from QSARs are compared between C12-14 alkylmorpholine and ethylmorpholine.

Based on the absence of any adverse effects in this study with the read-across substance, ethylmorpholine on reproductive and developmental parameter, the NOAEL for reproductive and developmental toxicity is considered to be 500 mg/kg bw/day. Further, based on clinical signs and decreased body weight gain and food consumption, the LOAEL and NOAEL for general toxicity in parent animals are considered to be 150 and 50 mg/kg bw/day, respectively.

Justification for selection of Effect on developmental toxicity: via oral route:
Only relevant guideline study available.

Justification for classification or non-classification

Based on the results of the reproduction and developmental toxicity studies, C12-14 alkylmorpholine does not need to be classified for reproduction / developmental toxicity according to EU CLP Regulation (EC) No. 1272/2008.