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REACH

N-cyclohexylcyclohexanamine 2-[1-[[[(1R)-1-[3-[(1E)-2-(7-chloroquinolin-2-yl)ethenyl]phenyl]-3-[2-(2-hydroxypropan-2-yl)phenyl]propyl]sulfanyl]methyl]cyclopropyl]acetate

EC number: 611-575-8 | CAS number: 577953-88-9

Life Cycle description
Uses advised against

Toxicological information

Endpoint summary

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

A Reproduction/ Developmental Screening Study in Rodents equivalent to OECD 421, conducted on dicyclohexylamine was taken as the key study, resulting in NOAEL of 40 mg/kg body weight/day for males and females. When the point of departure was adjusted to account for the molecular weights of the molar equivalents in the registered substance, the adjusted NOAEL was 169.2 mg/kg/day for Montelukast.DCHA.

In addition, a 2 generation reproductive toxicity study in rodents, equivalent to OECD 416 was conducted on sodium Montelukast, which resulted in a NOAEL of 100 mg/kg/day for males and females. When the point of departure was adjusted to account for the molecular weights of the molar equivalents in the registered substance, the adjusted NOAEL was 131 mg/kg/day for Montelukast.DCHA.

Selection of the point of departure also took into account the appropriate adjustment factors to allow the derivation of the most conservative DNEL value.

Link to relevant study records

Referenceopen all close all

Reference 1

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

GLP compliance:

yes

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles River Japan
- Age at study initiation: 8 weeks
- Weight at study initiation: 306 – 335 g for males and 201 – 224 g for females
- Fasting period before study: N/A
- Housing: , the animals were kept separate in bracket-type wire mesh cages (W 410 × D 350 × H 170 mm: Lead Engineering Co., Ltd.) divided in two. A total of two animals, one male and one female, were housed together in the aforementioned cages during the mating period and the dam and pups were housed together in plastic econ cages (W 340 × D 400 × H 185 mm: Clea Japan) with a floor covering (white flakes: Charles River Japan) for the period from 17 days of gestation through four days of lactation.
- Diet (e.g. ad libitum): ad libitum solid food NMF (irradiation-sterilized and autoclave-sterilized)
- Water (e.g. ad libitum): ad libitum tap water (Gotenba Municipal Waterworks water: automated water supply equipment used).
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 3°C
- Humidity (%): 50 ± 20%,
- Air changes (per hr): of 10 - 15 times/hour
- Photoperiod (hrs dark / hrs light): 12 hours (7:00 a.m. to 7:00 p.m.).

IN-LIFE DATES: From: To:

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

VEHICLE
- Justification for use and choice of vehicle (if other than water):concentrations of the corn oil solution were stable after being stored for eight days refrigerated (approximately 4°C) away from the light followed by being stored at room temperature away from the light for 24 hours
- Concentration in vehicle:0, 4, 8 and 16 mg/ml
- Amount of vehicle (if gavage): 5 ml/kg
- Lot/batch no. (if required): chemical grade, Nacalai Tesque, lot number: V7R2020
- Purity: Chemical grade

Details on mating procedure:

After having administered the test substance for the 14-day pre-mating period, males and females of the same group were housed together overnight in one-on-one pairs. The cohabitation period lasted until copulation was confirmed, up to 14 days at most. The formation of a copulatory plug or the confirmation of sperm in the vaginal smear was regarded as confirmation of copulation and this day was considered ‘Day 0’ of gestation.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

In formulating the test solution, the necessary amount of the test substance was measured for each concentration, it was dissolved in corn oil (chemical grade, Nacalai Tesque, lot number: V7R2020), and the specified amount was formulated. Test solution formulation was performed at a frequency of once per week as a general rule because it was confirmed at the Bozo Research Center that the test substance 4 and 40 mg/mL concentrations of the corn oil solution were stable after being stored for eight days refrigerated (approximately 4°C) away from the light followed by being stored at room temperature away from the light for 24 hours (Attached Data 2). After preparation, the daily amounts of the test solution were dispensed into brown glass bottles and stored refrigerated (approximately 4°C) away from light.
The percentage of the indicated value was always within the range of 97 – 101% and the concentrations were appropriate when each concentration of the test solution was confirmed at the Bozo Research Center using two administrations, one from before the start of administration to males and females and one in the final week of administration to males.

Duration of treatment / exposure:

Exposure period: males: 49 days; females from 14 days before mating to day 3 of lactation
Premating exposure period (males): 14 days
Premating exposure period (females): 14 days
Duration of test: males: 50 days, females: day 4 post partum

Frequency of treatment:

once daily

Details on study schedule:

Number of generation studies: 1

Remarks:

Doses / Concentrations:
0 mg/kg bw/day
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
20 mg/kg bw/day
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
40 mg/kg bw/day
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
80 mg/kg bw/day
Basis:
nominal conc.

No. of animals per sex per dose:

12 (twelve)

Control animals:

yes, concurrent vehicle

Details on study design:

Rationale for dosages
The dosages were determined using the results of the preliminary repeated dose 2-week oral administration study (Bozo Research Center, test number: U-1417, dosage: 0, 20, 40, 80, and 160 mg/kg) as a reference. Two of the five males and four of the five females in the 160 mg/kg dosage group died. There were no cases of death in the 80 mg/kg dosage group, but salivation was observed in both males and females in the clinical sign observations. No obvious changes in weight or food consumption were observed in the males of that group, but inhibited weight growth and a decrease in food consumption were observed in the females. However, no effects from administration of the test substance were observed on the female estrous cycle, necropsy findings, or organ weight. No obvious effects from the administration of the test substance were observed in the 20 or 40 mg/kg dosage groups other than the salivation that was observed in the 40 mg/kg dosage group. Consequently, the high dosage in this study was set at 80 mg/kg, at which effects on female body weight and food consumption was observed but at which there were no cases of death and the intermediate and low dosages were set at 40 and 20 mg/kg by dividing by a common ratio of two.

For the assignment of animals to each group, the animals selected by the criteria shown in ‘Section 2. Test animals’ were stratified by weight on the day of grouping (administration start day) and this was conducted through a combination of a block placement method and a random sampling method (the necessary groups were configured with the block placement method and the test groups and the individual numbers in the groups were allotted randomly) such that each group’s average weight was as equal as possible.

62 males and 62 females were purchased at seven weeks old, and after one week of quarantine and habituation, 48 males with no abnormal clinical indications and that showed good weight gain were selected, and after obtaining vaginal smears for all of the females for five days from the day after transport and observing the estrous cycles, 48 females that indicated normal estrous cycles and that had no abnormal clinical indications and showed good weight gain, just like with the males, were selected and administration was started at eight weeks old. The weight range at the start of administration was 306 – 335 g for males and 201 – 224 g for females. The surplus males after the groups were formed and the females with abnormal estrous cycles were euthanized under deep ether anesthesia after the group formation was completed and the other females were put down in the same manner after the mating period was ended.

Positive control:

Not applicable

Parental animals: Observations and examinations:

1) Males (P)
(1) Clinical sign observation
Clinical sign observation was conducted on the outer body surface, nutrition status, and behavior three times a day, pre-administration, immediately post-administration, and two hours after administration. However, the observation on Saturdays and holidays occurred only pre-administration and immediately post-administration.
(2) Body weight measurement
Body weight was measured pre-administration on the first day of administration, then between 8:30 a.m. – 12:30 p.m.at four days, eight days, 11 days, 15 days, 22 days, 29 days, 36 days, and 43 days, and on the necropsy day (50 days after the start of administration).
(3) Food consumption measurement
For food consumption, the remaining food was measured between 8:30 a.m. – 12:30 p.m. on the same days that body weight was measured, excluding the mating period and one day’s food consumption was calculated by the difference from the previous day’s food consumption.

2) Females (P)
(1) Clinical sign observation
Clinical sign observation was conducted on the outer body surface, nutrition status, and behavior three times a day, pre-administration, immediately post-administration, and two hours after administration. However, the observation on Saturdays and holidays occurred only pre-administration and immediately post-administration.
(2) Body weight measurement
Weight was measured between 8:30 a.m. – 12:30 p.m. during the pre-mating period before administration at one day, then at four days, eight days, 11 days, and 15 days, followed by at zero days, seven days, 14 days, and 21 days of gestation during the gestation period, followed by at zero days and four days of lactation during the lactation period.
(3) Food consumption measurement
For food consumption, the remaining food was measured between 8:30 a.m. – 12:30 p.m. on the same days that weight was measured during the pre-mating period, then at one day, seven days, 14 days, and 21 days of gestation during the gestation period, followed by at one day and four days of lactation during the lactation period, and daily food consumption was calculated from the difference from the previous day’s food consumption.

Oestrous cyclicity (parental animals):

Vaginal smear examination
Vaginal smears were obtained from all females during the pre-mating administration period until copulation was established and were examined microscopically. The vaginal smear images during the pre-mating administration period were classified into proestrus, estrus, postestrus, and anestrous, and the frequency of estrus stage images and the number of days from one estrus stage until the next estrus stage (estrous cycle) were examined. The presence of sperm in the vaginal smear was checked during the mating period.

Sperm parameters (parental animals):

not examined

Litter observations:

The dams delivered naturally and the presence of any delivery abnormalities was observed. Confirmation of delivery completion was conducted every day from 21 days through 23 days and if delivery had ended by 10:30 a.m., that day was considered ‘Day 0’ of lactation. If delivery occurred after 10:30 a.m., the following day was considered ‘Day 0’ of lactation. For dams for which a completed delivery had been confirmed, they were left to care for their pups until Day 4 of lactation and their lactation condition was observed using nest building, retrieving, and lactation as the indicators.

Pups (F1)
(1) Pup observation
At zero days of lactation, we counted the number of live born and the number of stillborn, and observed the existence of external malformations. Pups with external malformations were fixed in a 10% formalin solution in a phosphate buffer and preserved. The gender of the live born pups was determined and their weight was measured, then they were cared for by the dam. The stillborn pups were also fixed in a 10% formalin solution in a phosphate buffer and preserved.
(2) Nursling observation and measurement
Nurslings were observed once a day each day to determine whether they were alive or dead. Weight was measured at zero days (lactation Day 0) and at four days after birth. At four days after birth, all pups were exsanguinated under ether anesthesia, necropsies were performed, and the presence of internal organ abnormalities was checked.

Postmortem examinations (parental animals):

Male: Necropsy and organ weight measurement
After the weight of all cases was measured the day after the final administration, the subjects were exsanguinated through the abdominal aorta under ether anesthesia, necropsied, and the internal organs and tissue were observed macroscopically. In addition, the testes and epididymis were harvested and weighed, then fixed in Bouin solution. Additionally, the organs and tissue in which abnormalities were observed in the necropsy were fixed in 10% formalin solution prepared in a phosphate buffer solution (1/15 M, pH 7.1 – 7.4) (hereinafter abbreviated as ‘10% formalin solution in a phosphate buffer’) and preserved.
Histopathological testing
The testes and epididymis of all cases were embedded in paraffin, segments were prepared for the control group and the high dosage group, hematoxylin-eosin staining and PAS dyeing was performed, and they were examined microscopically.

Female: After the weight of all cases was measured at four days of lactation, the subjects were exsanguinated through the abdominal aorta under ether anesthesia, necropsied, the internal organs and tissue were observed macroscopically, and the number of corpora lutea and the number of implantation sites were checked. In addition, the organs and tissue in which abnormalities were observed in the necropsy were fixed in a 10% formalin solution in a phosphate buffer and preserved. The two cases (No. 4102, 4110) from the 80 mg/kg dosage group that died during gestation and the six cases from the same group (No. 4101, 4106, 4108, 4109, 4111, 4112) in which all of the pups were stillborn or all of the pups died during the lactation period were necropsied in the same manner when they were discovered.
Histopathological testing
The ovaries of all cases were embedded in paraffin, segments were prepared for the control group and the high dosage group, hematoxylin-eosin staining was performed, and they were examined microscopically.

Postmortem examinations (offspring):

Pups with external malformations were fixed in a 10% formalin solution in a phosphate buffer and preserved. The stillborn pups were also fixed in a 10% formalin solution in a phosphate buffer and preserved. At four days after birth, all pups were exsanguinated under ether anesthesia, necropsies were performed, and the presence of internal organ abnormalities was checked.

Statistics:

Statistical analysis was performed using the following methods and the two-sided significance level was 5 and 1%. For the delivery rate, birth rate, and viability rate, the mean value and the rate were obtained for each dam and compared. In addition, the data of one female from the 20 mg/kg dosage group for which incorrect administration was thought to have occurred was excluded from the copulation rate and the fertility rate data and was excluded from the count.
1) Multiple comparison tests
A variance uniformity assay was performed for each group using the Bartlett method. As a result, when the variance was uniform, a one-way analysis of variance was performed and if a significant difference between groups was observed, a paired comparison test was performed for the control group and each administration group using the Dunnett method. If the variance was not uniform, a Kruskal-Wallis rank test was performed, and if it was significant, a Dunnett’s test was performed for the difference in the average of the ranks for the control group and each administration group.
Weight, food consumption, frequency of estrus images, estrous cycle, number of days of cohabitation, gestation period, organ weight, number of corpora lutea, number of implantation sites, number of live born pups, sex ratio, implantation rate, delivery rate, birth rate, viability rate

2) x2 test
Copulation rate, fecundation rate, delivery rate

3) Mann-Whitney U test
This was performed for the frequency of occurrence and intensity of degree for findings in the histopathological testing.

Reproductive indices:

Copulation rate (%) = (number of animals with confirmed copulation/ number of animal matings) × 100
Fertility rate (%) = (number of gestating animals/number of animals with confirmed copulation) × 100
Parturition rate (%) = (number of dams that delivered live pups/number of gestating dams) × 100
Gestation period (days) = Day 0 of lactation (delivery confirmation day) – Day 0 of gestation

Offspring viability indices:

Gender ratio = Males/ (males + females)
Viability rate (%) = (number of surviving pups at Day 4 of lactation/number of live born pups at Day 0 of
lactation) × 100
Delivery rate (%) = (Total number of pups delivered/number of implantation sites) × 100
Birth rate (%) = (number of surviving pups at Day 0 of lactation/total number of pups delivered) × 100
Implantation rate (%) = (number of implantation scars/number of corpora lutea) × 100

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg/day (M/F)

Mortality:

mortality observed, treatment-related

Description (incidence):

2 females 80 mg/kg/day

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg/day decreased (M/F)

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg/day decreased (M/F)

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):

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg/day F- poor pup retrieval

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Repeated dose toxicity

1. Effects on males (P)
1) Clinical signs
No changes were observed in clinical signs in groups with dosages of 40 mg/kg or lower. Salivation was observed temporarily or continuously immediately post-administration in 11 out of 12 cases (all except No. 4008) in the 80 mg/kg dosage group starting at seven days of administration. However, other neurological indications were not observed, so salivation was not determined to be an effect of administration of the test substance.

2) Body weight
The weight on each measurement day and the amount of weight gain in the groups with dosages of 40 mg/kg or lower were equivalent to that of the control group and no effect due to the administration of the test substance was observed. Weight gain was inhibited in the 80 mg/kg dosage group and a significant difference was observed in the measurement values at 29 days and at the day after final administration (50 days after the start of administration) as well as in the amount of weight gain between this group and the control group.

3) Food consumption
Significantly lower values were observed for food consumption at 22 days in the 80 mg/kg dosage group, but food consumption in the test substance administration groups was equivalent to the control group overall and no effect was observed due to administration of the test substance.

4) Necropsy findings
Other than dark red spots that were observed on the liver of one case in the 80 mg/kg dosage group (No. 4001) and that were considered incidental findings, macroscopic abnormalities were not observed in the internal organs or tissue in any of the cases.

5) Organ weight
No significant difference was observed between the control group and the test substance administration groups in the absolute weight of the testes or epididymis. In terms of relative weight, the testes weight in the 80 mg/kg dosage group was high and a significant difference was observed in the weight of the right side and in the bilateral weight. The high relative weight of the testes was considered to be a change caused by the low final body weight.

6) Histopathological testing
In an examination of the testes and epididymis performed in the control group and the 80 mg/kg dosage group, minor sperm retention and decreased sperm and cell debris in the lumen of the epididymis were observed in one case of the control group and one case of the 80 mg/kg dosage group (control group: No. 1005, 80 mg/kg dosage group: No. 4012), and mild sperm granuloma was observed in the epididymis of one case in the 80 mg/kg dosage group (No. 4006), but these were considered incidental changes from the histological properties.

2. Effects on females (P)
1) Clinical signs
No changes in clinical signs were observed throughout the pre-mating administration period, the mating period, the gestation period, or the lactation period in the groups with dosages of 40 mg/kg or lower. One case died at 21 days of gestation and one died at 22 days of gestation (No. 4102, 4110) in the 80 mg/kg dosage group. Salivation was observed immediately after administration in all of the cases starting at eight days and it was observed temporarily or continuously during the period up to three days of lactation, and unkempt fur was recorded prior to death (22 days of gestation) in one of the cases that died (No. 4102). However, no neurological symptoms other than salivation were observed in that group, so the salivation was not determined to be an effect of the administration of the test substance. In addition, clinical signs including a prone position, oligopnea, hypothermia, and poor pup retrieval were recorded in one case (No. 4108) two hours after administration after delivery had been completed at 22 days of gestation. During the lactation period of the same group, two cases of unkempt fur (No. 4108, 4111) were observed as clinical sign changes, and poor pup retrieval was observed in seven cases (No. 4101, 4104, 4106, 4107, 4108, 4109, 4112).
It is not indicated in the table, but one case of wheezing (No. 2106) was observed in the 20 mg/kg dosage group from 12 days to 15 days and the accumulation of white matter in the chest cavity was observed in the necropsy, so incorrect administration was believed to have occurred in that group.

2) Body weight
In the groups with dosages of 40 mg/kg or lower, the weights on each measurement day and the amount of weight gain were equivalent with those of the control group during the pre-mating period, the gestation period, and the lactation period and no effects from the administration of the test substance were observed. Weight gain was inhibited in the 80 mg/kg dosage group and a significant difference was observed between that group and the control group in the measurement values at four days, eight days, and 11 days, as well as at 21 days of gestation and at four days of lactation. In addition, the weight gain in each period was low and a significant difference was observed between that group and the control group in the weight gain amount in the gestation period.

3) Food consumption
Significantly lower values were observed in food consumption at one day of gestation in the groups with dosages of 40 mg/kg or lower, but overall, the values were equivalent to those of the control group throughout the pre-mating administration period, the gestation period, and the lactation period, and no effects from administration of this test substance were observed. Food consumption in the 80 mg/kg dosage group was lower than in the control group and significant differences were observed between the two groups at four days, 11 days, and 15 days during the pre-mating administration period, at one day and 21 days of gestation in the gestation period, and at one day and at four days of lactation in the lactation period. The decrease in food consumption of that group was remarkable during the lactation period.

4) Necropsy findings
A diaphragmatic hernia and dark red spots in the glandular stomach were observed in one case (No. 4102) of the 80 mg/kg dosage group that died at 22 days of gestation and unkempt fur was recorded in the external findings. No other macroscopic abnormalities were observed in the internal organs or tissue in any of the cases. The findings from the aforementioned fatal cases were not observed in other cases of the same group and were congenital abnormalities, so they were determined to be incidental findings.

5) Histopathological testing
There were no abnormal findings in any of the cases in the examination of the ovaries that was performed in the control group and the 80 mg/kg dosage group.

II. Reproduction toxicity
1. Effects on parent animal (P)

1) Estrous cycle
The estrous cycles of the test substance administration groups, namely the frequency of estrus stage images and the number of days from one estrus stage until the next estrus stage, were equivalent with those of the control group and no significant differences were observed.

2) Copulation rate and fertilization rate
Copulation was established within four days of cohabitation in all of the cases in the control group and the test substance administration groups and the copulation rate for each group was 100%. In addition, there was no significant difference observed between the control group and the test substance administration groups in terms of the average number of days required until copulation was established.
Gestation was established in all of the cases of the control group and the test substance administration groups and the fertilization rate of all groups was 100%.

3) Gestation, delivery, and lactation
The gestation period in the test substance administration groups was basically equivalent to that of the control group and no significant differences were observed. Delivery abnormalities were not observed in the control group or any of the test substance administration groups. No abnormalities were observed in lactation of the groups with dosages of 40 mg/kg. However, as mentioned above, poor retrieving was observed in seven cases (No. 4101, 4104, 4106, 4107, 4108, 4109, 4112) of the 80 mg/kg dosage group.

4) Number of dams with live born pups, gestation rate, number of corpora lutea, number of implantation sites and implantation rate
The number of dams with live born pups included all of the cases in the 20 and 40 mg/kg dosage groups and nine out of 10 in the 80 mg/kg dosage group and no significant differences were observed between the control group and the test substance administration groups in terms of the gestation rate. No significant differences in the number of corpora lutea, the number of implantation scars, or the implantation rate were observed between the control group and the test substance administration groups.

Dose descriptor:

NOAEL

Effect level:

ca. 80 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

Key result

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

reproductive performance

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, treatment-related

Description (incidence and severity):

80 mg/kg/day viability and birth rate significantly lower

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

lower at 80 mg/kg/day

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:

not examined

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Effects on pups (F1)
1) Number of live born pups, number of stillborn pups, delivery rate and birth rate
No significant difference in the number of live born pups, the number of stillborn pups, or the birth rate was observed between the groups with dosages of 40 mg/kg or lower and the control group. However, in the 80 mg/kg dosage group, the number of stillborn pups was significantly higher, the number of viable pups was significantly lower, and the birth rate was significantly lower. No significant difference in the delivery rate was observed between the control group and the test substance administration groups.

2) Sex ratio, external malformations, and viability
A significant difference in the sex ratio was not observed between the control group and the test substance administration groups. The only external malformations in the pups were observed in one case in which vestigial tail and anal atresia was observed from one dam (No. 3101) of the 40 mg/kg dosage group.
No significant difference was observed in the viability rate between the control group and the groups with dosages of 40 mg/kg or lower. However, there were many deaths in the lactation period in the 80 mg/kg dosage group and only four out of the nine dams had surviving pups at four days of lactation. Consequently, the viability rate of that group was remarkably low and a significant difference was observed when compared with the control group.

3) Body weight
Weight was mostly equivalent with that of the control group for both males and females at zero days and at four days after birth for the groups with dosages of 40 mg/kg or lower and no significant difference was observed. In the 80 mg/kg dosage group, weight for both males and females at zero days and at four days after birth was low compared with the control group and a significant difference was observed between the two groups at zero days after birth.

4) Necropsy findings
In the necropsies performed at four days after birth, there were findings of thymic remnant in the neck, malposition of the spleen, abnormal bifurcation of the artery from the aortic arch, and nodules in the urinary bladder in the control group and the 20 and 40 mg/kg dosage groups in small numbers, but these findings were not observed in the 80 mg/kg dosage group.

Key result

Dose descriptor:

NOAEL

Generation:

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

Reproductive effects observed:

not specified

Conclusions:

No effects were observed on the estrous cycle, copulation, or fertility, or in the gestation period or delivery in any of the administration groups due to administration of the test substance. However, many dams with poor pup retrieval were observed in the 80 mg/kg dosage group during lactation and effects were observed on pup survival and development due to administration of the test substance. Consequently, the reproductive development no observed effect level was determined to be 80 mg/kg/day for males, 40 mg/kg/day for females, and 40 mg/kg/day for pups.

Executive summary:

A preliminary reproduction toxicity screening test of dicyclohexylamine was performed at dosages of 0 (control group), 20, 40, and 80 mg/kg with 12 males and 12 females Sprague-Dawley SPF rats [Crj; CD (SD)] per group in which it was administered to males for a 14-day pre-mating period and through the mating period until the day before necropsy and to females for a 14-day pre-mating period, through the mating period, the gestation period, and delivery until Day 3 of lactation.

In males (P), inhibited weight growth was observed at 80 mg/kg. However, no effects on clinical signs, food consumption, necropsy findings, testes or epididymis weight or the histopathological findings of these organs were observed in that group due to administration of the test substance. At the same time, no effects on clinical signs, weight, food consumption, necropsy findings, testes or epididymis weight were observed in the groups with dosages of 40 mg/kg or lower.

In females (P), one case died at 21 days of gestation and one died at 22 days of gestation in the 80 mg/kg dosage group. In addition, unkempt fur was recorded in the case that died at 22 days of gestation and a prone position, oligopnea, hypothermia, and poor pup retrieval were recorded in one case after delivery had been completed at 22 days of gestation. Unkempt fur and poor retrieval were observed as clinical sign changes during the lactation period in that group. Furthermore, weight gain was inhibited and low values were indicated for weight gain and food consumption in the pre-mating administration period, the gestation period, and the lactation period. However, no effects were observed in the necropsy findings or the histopathological test findings of the ovaries in that group due to administration of the test substance. No effects on clinical signs, weight, food consumption, or necropsy findings were observed in the groups with dosages of 40 mg/kg or lower.

In the 80 mg/kg dosage group, two females died, inhibited weight gain was observed in males and females, and decreased food consumption was observed in females. Consequently, we determined the general toxicity no observed effect level for males and females to be 40 mg/kg/day.

Looking at the parent animal (P) reproductive development toxicity, no effects on the female estrous cycle were observed due to administration of this test substance, nor were any effects observed for male and female copulation or fertility, or for the gestation period. In addition, delivery abnormalities were not observed in the control group or in any of the test substance administration groups. Many dams with poor pup retrieval were observed during lactation in the 80 mg/kg dosage group and only four dams had surviving pups up to four days of lactation. However, lactation abnormalities were not observed in the groups with dosages of 40 mg/kg or lower. At the same time, no effects were observed on the number of dams with live born pups, the gestation rate, the number of corpora lutea, the number of implantation sites, or the implantation rate.

A significantly lower number of viable pups and a significantly lower birth rate were observed. However, no effect was observed on the number of live born pups, the number of stillborn pups, or on the gestation rate due to administration of this test substance in the groups with dosages of 40 mg/kg or lower. In addition, no effect was observed on the delivery rate in any of the groups due to administration of the test substance.

No effect was observed on the sex ratio of pups due to administration of the test substance and external malformations caused by administration of the test substance were not observed. There were many pup deaths in the 80 mg/kg dosage group during the lactation period and the viability rate in that group was remarkably low. However, no effect was observed on the viability rate of groups with dosages of 40 mg/kg or lower due to administration of the test substance. Pup weight was low for both males and females of the 80 mg/kg dosage group at zero days and four days after birth, but no effect on weight was observed in the groups with dosages of 40 mg/kg or lower due to administration of the test substance. No abnormalities thought to be caused by administration of the test substance were observed in the necropsies of the pups at four days after birth.

Reference 2

Endpoint:: two-generation reproductive toxicity
Type of information:: experimental study
Adequacy of study:: weight of evidence
Study period:: 24-08-1992 to 22-06-1993
Reliability:: 2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:: comparable to guideline study with acceptable restrictions
Qualifier:: equivalent or similar to guideline
Guideline:: OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
Deviations:: not specified
GLP compliance:: yes
Limit test:: no
Justification for study design:: The objective of this study was to assess the effects of L-706,631
administration to Fo female rats on reproductive performance and
fertility and to evaluate the effects on growth, development,
behavior, reproductive performance and fertility of the F1 generation.
Specific details on test material used for the study:: a. Test Article: L-706,631
b. Lot Number: L-706,631-00lMOlS
c. Purity: 99.4 area%, 99.6 weight% based on HPLC
d. Factor: 1.04
Species:: rat
Strain:: Sprague-Dawley
Remarks:: Crl:CD®(SD) BR
Sex:: female
Details on test animals or test system and environmental conditions:: Source: Charles River Laboratories, Raleigh, NC
Number Assigned to Study: 160 Fo Animals

Age at Initiation: Approximately 9 weeks

Weight at Initiation: 197 to 267 grams

Identification Method:
Fo - ear notch F1 - foot tattoo, tail tattoo

Environmental Conditions:
a. Housing:
F0 females were housed singly in wire-mesh metal
bottom cages prior to and after mating until gestational
day 21. Approximately on gestational day (GD) 15, Fo
females scheduled for delivery were transferred to
individual clear plastic boxes containing dry bedding in
preparation for delivery of pups. Maternal animals and
pups remained in this type of cage through the lactation
period. Room temperature was maintained at 20.6° to
23.9°C; room light's were set with a timer for a 12-hour
light and 12-hour dark cycle.

b. Diet:
The rats had free access to Purina Certified Rodent
Chow #5002 and tap water.
Route of administration:: oral: gavage
Vehicle:: CMC (carboxymethyl cellulose)
Remarks:: 0.5% aqueous
Details on exposure:: PREPARATION OF DOSING SOLUTIONS:
Suspensions L-706,631 in 0.5% methylcellulose were
prepared daily and kept constantly stirred during dosing.

VEHICLE
- Justification for use and choice of vehicle (if other than water): not given
- Concentration in vehicle: 10, 20 and 40 mg/ml
- Amount of vehicle (if gavage): 5 ml/kg
- Lot/batch no. (if required): (Dow Chemical Company Lot #MM89090311A)
- Purity:
Details on mating procedure:: Fo females were housed with untreated males of the same
strain in a 1:1 ratio for a maximum of 16 nights. A vaginal
lavage was examined each morning for the presence of sperm.
The day of finding plug and/or sperm was considered GD O.
Analytical verification of doses or concentrations:: yes
Details on analytical verification of doses or concentrations:: Samples of dosing suspensions were collected at the
start of dosing and analyzed for uniformity and
concentration. Samples of
dose suspensions were
collected in Drug Week 7 and 9 and were assayed for
concentration. All assay results were within acceptable
limits. The compound has been shown to be stable in
this vehicle under the conditions of this study.
Duration of treatment / exposure:: F0 females were dosed for 14 days prior to
cohabitation, during cohabitation, and through GD 20 for
females that were cesarean-sectioned or
through Lactation Day (LD) 20 for females allowed to deliver
their litters.
Frequency of treatment:: Once daily
Details on study schedule:: - F1 parental animals not mated until 7-8 weeks after selected from the F1 litters.
- Selection of parents from F1 generation when pups were 24-28 days of age.
- Age at mating of the mated animals in the study: 11-12 weeks
Dose / conc.:: 50 mg/kg bw/day
Dose / conc.:: 100 mg/kg bw/day
Dose / conc.:: 200 mg/kg bw/day
No. of animals per sex per dose:: 40
Control animals:: yes, concurrent vehicle
Details on study design:: - Dose selection rationale: The doses for this study were selected based on an
oral range-finding study in pregnant rats (TT #92-717-1)
with doses up to 800 mg/kg/day in which decreases in
maternal body weights were observed at doses of
200 mg/kg/day and above.

- Rationale for animal assignment (if not random): Females were assigned to the following groups based on a weight-balanced random allocation schedule:
- Other:
Parental animals: Observations and examinations:: CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: 1-5 hours post dosing

BODY WEIGHT: Yes
- Time schedule for examinations: Recorded on Premating days 1, 4, 8, 11, and 14; Drug
Days 22, 29, 36, 43, 51, and 54 (i.e., during and after cohabitation), if needed; GD O, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22, and 24; and LD 0, 3, 7, 10, 14, 17, and 21.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Measured for all animals during the following
intervals: Premating days 1 - 5 and 8 - 12; GD 1 - 5,
8 - 12, and 15 - 19; and LD 1 - 5 and 8 - 12.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No
- Time schedule for examinations:

OTHER:
Oestrous cyclicity (parental animals):: Not determined
Sperm parameters (parental animals):: Not determined
Litter observations:: STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

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,

The following parameters were examined in [F2] offspring:
On PND O, the pups were counted, weighed, sexed,
examined for external malformations, and mortality noted.

GROSS EXAMINATION OF DEAD PUPS:
yes, for external abnormalities; possible cause of death was not determined for pups born or found dead.

ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY:

ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY:
Postmortem examinations (parental animals):: Sacrifice and Pregnancy Status (Females Selected for Cesarean Section):
Approximately twenty females per group were euthanized on GD 21 by co2
asphyxiation. The uterus of each female was examined to determine pregnancy status. The number
of corpora lutea were counted.
Sacrifice and Pregnancy Status (Females Selected forNatural Delivery):
Females that delivered were euthanized by co2
asphyxiation between LD 23 to 25 and the uterus of each
was examined to count me trial glands. Mated females
that did not deliver pups were euthanized on the
presumed GD 24, and non-mated females were euthanized
24 days after the end of the mating period.

Necropsy:
A gross examination of thoracic and abdominal viscera
was done on all sacrificed females.
Postmortem examinations (offspring):: Sacrifice and Necropsy:
Approximately one-half of the F1 males and
females which were not used for mating were
euthanized by co2 asphyxiation and discarded
without further examination in Postnatal Week 17 or 18
2
All F1males used for mating were euthanized or by co2
asphyxiation in Postnatal Weeks 17-18.
The testes and epididymides of these males were
examined grossly, weighed, and preserved in
Bouin 's fixative.
These tissues from the control and high-dose groups, as well as testes
from other groups which were of uncertain gross
character were examined for histomorphological
changes. Remaining tissues were discarded
without examination. F1 females which delivered
were euthanized by co2 asphyxiation between LD O
to 3 and the uterus of each female was examined
to count metrial glands. Mated females that did
not deliver pups were similarly euthanized on the presumed GD 24.
Non-mated females were similarly euthanized 24 days after the end of
the cohabitation period.
Statistics:: Statistical analyses were done by an analysis of
variance or covariance.
A rankit method was used to normalize nonparametric data. Results were considered to
be statistically significant if P < 0.05.
A trend analysis was used to determine if there was a significant
(P < 0.05) trend with increasing dosage across all
treatment groups. If there was a significant (P < 0.05)
trend, data from the high dose group were excluded and the
trend test was repeated (see Appendix I for references).
This process was repeated until the trend test was not
statistically significant (P > 0.05).
Reproductive indices:: Average length of gestation (F0 and F1 females)
Percent mated females per females cohabited (F0 and F1)
Fecundity index of females (F0 and F1)
Fertility index of females (F0 and F1)
Mating index (F0 and F1)
Average corpora lutea per F0 female
Average resorptions + dead fetuses per implants (F0)
Average implants per pregnant female (F0 and F1)
Average postimplantation survival (F0 only)
Offspring viability indices:: Average live F1 fetal weight (sexes separate)
Average live F1 fetuses per pregnant female
Average live F1 and F2 pups per litter on PND0
F1 pup deaths between PND 1-3 and 4-21
Average live F1 pup weights on PND O, 7, 14, and 21
(male and female separately, adjusted for length of gestation and number of live pups per litter on postnatal Day O where appropriate)
Average trials to criterion in the Passive Avoidance test (F1 male and female separately)
Mean horizontal activity (open field test)
Mean Vmax' Tmax trials 1-50, in auditory startle habituation
Average F1 postweaning weight gains between Postnatal Weeks 1 to 9 were analyzed for linear, average, and quadratic time responses (male and female separately)
Average estimated mean day of occurrence of vaginal canalization and preputial separation in F1 animals
Live F2 pups per litter
Average live F2 pup weight on PND 0 (male and female separately, adjusted for length of gestation and number of live pups per litter
Clinical signs:: effects observed, non-treatment-related
Description (incidence and severity):: Sporadic occurrences of postdosing salivation were observed in a few animals in all treated groups. Frequently this occurred immediately after dosing or when the dose was partially regurgitated indicating that this may be a reaction to the taste of the drug. This slight sporadic salivation in few animals is considered to have no toxicologic significance. There were no other treatment-related signs.
Mortality:: no mortality observed
Description (incidence):: There were no treatment-related deaths or abortions.
Body weight and weight changes:: effects observed, non-treatment-related
Description (incidence and severity):: There were no treatment-related changes in F0 female body weight gain. In the two week premating interval there were significant (P < 0. 05) decreases in average female body weight of 20, 16.7 and 23.3 percent below controls in the 50, 100 and 200 mg/kg/day groups, respectively; these showed no dose-response are therefore not considered treatment-related. There were no treatment-related changes in maternal body weight gain during gestation or lactation.
Food consumption and compound intake (if feeding study):: no effects observed
Description (incidence and severity):: There were no treatment-related effects on food consumption.
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
Histopathological findings: non-neoplastic:: not examined
Histopathological findings: neoplastic:: not examined
Other effects:: no effects observed
Reproductive function: oestrous cycle:: not examined
Reproductive function: sperm measures:: not examined
Reproductive performance:: effects observed, treatment-related
Description (incidence and severity):: gestation length- no significant effects observed
% mated females- no significant effects observed
fecundity index- significant reduction at 200mg/kg/day (82%)
fertiltiy index- significant reduction at 200mg/kg/day (80%)
Mating index- no significant effect observed
: Key result
Dose descriptor:: NOAEL
Effect level:: 100 mg/kg bw/day
Based on:: test mat.
Sex:: female
Basis for effect level:: reproductive performance
: Key result
Critical effects observed:: no
Clinical signs:: no effects observed
Description (incidence and severity):: There were no treatrnent-related physical signs observed in the F1 pups during lactation. There were no treatment-related physical signs among F1 rats during the postweaning period. There were no treatment-related effects from mating until sacrifice
Mortality:: mortality observed, non-treatment-related
Description (incidence):: There were no treatment-related or statistically significant effects (P >0. 05) on preweaning pup survival. There were no treatment-related deaths. Three animals, one from each of the control , 50 mg/kg/day and 100 mg/kg/day groups were found dead. There were no physical signs nor cause of death determined for these animals. There were no postweaning deaths in the 200 mg/kg/day group. There were no treatment-related effects from mating until sacrifice.
Body weight and weight changes:: effects observed, treatment-related
Description (incidence and severity):: There were no treatment-related effects on F1 pup body weight in the 50 and 100 mg/kg/day· groups. In the 200 mg/kg/day group there were significant (P< 0.05) slight treatment-related decreases in pup body weight on Days 7, 14, and 21 in males and females during weaning.
There were no treatment-related effects on. average F1 body weight gain during the period from weaning to cohabitation (i.e., postweaning weeks 1 to 9). There were no treatment-related effects during or after co-habitation. There were no treatment related effects on maternal weigt changes during pregnancy.
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:: no effects observed
Haematological findings:: not examined
Clinical biochemistry findings:: not examined
Urinalysis findings:: not examined
Behaviour (functional findings):: effects observed, non-treatment-related
Description (incidence and severity):: There were no treatment-related effects on auditory startle habituation. In the 200 mg/kg/day group there was a significant (P< 0.05) decrease in Vmax (peak amplitude of movement) (Trials 1-50) in females only (282 in controls vs 200 in the 200 mg/kg/day group); the effects in the high dose females are not considered treatment-related.
Passive Avoidance: There were no treatment-related effects as assessed by trials to criterion. In trial one, males in the 200 mg/kg/day group had a significant (P <0.05) Increased performance over controls; this increase in performance is considered due to normal variability and is not considered an effect of treatment.
Open field Motor Activity: There were no treatment-related or statistically significant (P > 0.05) effects as assessed by average horizontal activity during the 60 min test period.
Immunological findings:: no effects observed
Organ weight findings including organ / body weight ratios:: no effects observed
Description (incidence and severity):: There were no treatment-'related changes in testicular weights of high-dose males used for breeding.
Gross pathological findings:: no effects observed
Neuropathological findings:: not examined
Histopathological findings: non-neoplastic:: no effects observed
Description (incidence and severity):: There were no treatment-'related changes in testicular and epididymal histomorphology of high-dose males used for breeding.
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
Description (incidence and severity):: There were no treatment-related and/or statistically significant (P > 0.05) effects as assessed by time to mating, mating index, percent mated females/females cohabited, fecundity or fertility indices, percent females with live pups, and length of gestation.
: Key result
Dose descriptor:: NOAEL
Effect level:: 100 mg/kg bw/day
Based on:: test mat.
Sex:: male/female
Basis for effect level:: body weight and weight gain
Clinical signs:: no effects observed
Description (incidence and severity):: There were no t reatrnent-related physical signs observed in the F1 pups during lactation. There were no treatment-related physical signs among F1 rats during the postweaning period. There were no treatment-related effects from mating until sacrifice
Mortality / viability:: mortality observed, non-treatment-related
Description (incidence and severity):: There were no treatment-related and/or statistically significant effects on embryonal/fetal survival in the L-706,631-treated groups as assessed by percent preimplantation loss, implants per pregnant female, total resorptions, percent resorptions plus dead fetuses per implants, and live fetuses per litter.
There were no treatment-related or statistically significant effects (P >0. 05) on preweaning pup survival. There were no treatment-related deaths. Three animals, one from each of the control , 50 mg/kg/day and 100 mg/kg/day groups were found dead. There were no physical signs nor cause of death determined for these animals. There were no postweaning deaths in the 200 mg/kg/day group. There were no treatment-related effects from mating until sacrifice.
Body weight and weight changes:: effects observed, treatment-related
Description (incidence and severity):: There were no treatment-related changes on average male or female fetal weights.
There were no treatment-related effects on F1 pup body weight in the 50 and 100 mg/kg/day· groups. In the 200 mg/kg/day group there were significant (P< 0.05) slight treatment-related decreases in pup body weight on Days 7, 14, and 21 in males and females during weaning.
There were no treatment-related effects on. average F1 body weight gain during the period from weaning to cohabitation (i.e., postweaning weeks 1 to 9). There were no treatment-related effects during or after co-habitation. There were no treatment related effects on maternal weigt changes during pregnancy.
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:: no effects observed
Description (incidence and severity):: There was no treatment-related ophthalmologic changes in F1 rats.
Haematological findings:: not examined
Clinical biochemistry findings:: not examined
Urinalysis findings:: not examined
Sexual maturation:: no effects observed
Description (incidence and severity):: There were no treatment-related or statistically significant (P > 0.05) effects on the estimated mean day of vaginal canalization or preputial separation
Organ weight findings including organ / body weight ratios:: no effects observed
Description (incidence and severity):: There were no treatment-'related changes in testicular weights of high-dose males used for breeding.
Gross pathological findings:: effects observed, non-treatment-related
Description (incidence and severity):: There were no treatment-related changes observed in external, visceral, and skeletal examinations of fetuses. The incidence of anomalies in the treated groups were comparable to control, lacked a dose response, or occurred in only a few fetuses. There was an increased incidence of incomplete ossification in the 200 mg/kg/day group (0 in control vs. 5 with incomplete ossified sternebra in the 200 mg/kg/day group). This is due to five fetuses in one litter (92-8670) in which the pups were generally lighter than average and is considered due to lower fetal weight in this litter and not an effect of L-706,631 on ossification.
There were no external malformations or variations observed in F1 pups from the 1-706,631 treated groups.
Histopathological findings:: no effects observed
Description (incidence and severity):: There were no treatment-'related changes in testicular and epididymal histomorphology of high-dose males used for breeding.
Behaviour (functional findings):: effects observed, non-treatment-related
Description (incidence and severity):: There were no treatment-related effects on auditory startle habituation. In the 200 mg/kg/day group there was a significant (P< 0.05) decrease in Vmax (peak amplitude of movement) (Trials 1-50) in females only (282 in controls vs 200 in the 200 mg/kg/day group); the effects in the high dose females are not considered treatment-related.
Passive Avoidance: There were no treatment-related effects as assessed by trials to criterion. In trial one, males in the 200 mg/kg/day group had a significant (P <0.05) Increased performance over controls; this increase in performance is considered due to normal variability and is not considered an effect of treatment.
Open field Motor Activity: There were no treatment-related or statistically significant (P > 0.05) effects as assessed by average horizontal activity during the 60 min test period.
Developmental immunotoxicity:: not examined
: Key result
Dose descriptor:: NOAEL
Generation:: F1
Effect level:: 100 mg/kg bw/day
Based on:: test mat.
Sex:: male/female
Basis for effect level:: body weight and weight gain
Clinical signs:: no effects observed
Description (incidence and severity):: There were no treatment-related effects noted at birth
Dermal irritation (if dermal study):: not examined
Mortality / viability:: no mortality observed
Description (incidence and severity):: There were no treatment-related and/or statistically significant (P > 0 .05) effects as assessed by implants per female, percent postimplantation survival, live
pups per litter, and percent live pups
Body weight and weight changes:: no effects observed
Description (incidence and severity):: There were no treatment-related effects at birth
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
Description (incidence and severity):: There were no treatment-related effects noted at birth.
Histopathological findings:: not examined
Behaviour (functional findings):: not examined
Developmental immunotoxicity:: not examined
: Key result
Reproductive effects observed:: yes
Lowest effective dose / conc.:: 200 mg/kg bw/day
Treatment related:: yes
Relation to other toxic effects:: reproductive effects in the absence of other toxic effects
Dose response relationship:: yes
Relevant for humans:: yes
Conclusions:: Fo maternal physical signs were limited to postdosing salivation observed sporadically in a few animals from all dose groups which are considered associated with or secondary to taste aversion to the drug.
Treatment-related Fo maternal toxicity was observed in the 200 mg/kg/day group as very slight decreases in fertility and fecundity indexes 15.8 and 13. 7 percent below controls, respectively.
There were no treatment-related effects on reproductive performance in the F0 generation based on mating, females with live pups, length of gestation,' and corpora lutea per dam.

There were no treatment-related gross lesions at necropsy.
There were no treatment-related effects on embryonal/fetal survival; fetal weight; fetal external, visceral, or skeletal morphology of the F1 generation.

Preweaning treatment-related toxicity in the F1 generation was limited to decreased pup weights (approximate range 5-10 percent) in both males and females in the 200 mg/kg/day group on PND 7, 14 and 21. There were no effects on preweaning F1 pup external morphology, or survival. During the postweaning period there were no treatment-related effects on survival, weight gain, appearance of developmental signs, tests of behavior (auditory startle habituation, passive avoidance, and open field motor activity), ophthalmological examination of the 1-706,631-exposed F1 generation.

There were no treatment-related effects on the reproductive performance of the F1 generation based on the above-mentioned F0 parameters (corpora lutea not evaluated), and including implants and live pups per litter, postimplantation survival, external morphology, and live F2 birth weight.

Based on the slightly decreased fertility and fecundity indexes and decreased Fi pup weights in the 200 mg/kg/day group the NOAEL (No Observed Adverse Effect Level) of 1-706,631 for reproductive and developmental toxicity is 100 mg/kg/day.

Effect on fertility: via oral route

Endpoint conclusion:: adverse effect observed
Dose descriptor:: NOAEL
: 169.2 mg/kg bw/day
Study duration:: subacute
Species:: rat

Effect on fertility: via inhalation route

Endpoint conclusion:: no study available

Effect on fertility: via dermal route

Endpoint conclusion:: no study available

Effects on developmental toxicity

Description of key information

In addition, a development toxicity in rodents, equivalent to ICH S5(R2) was conducted on sodium Montelukast, which resulted in a NOAEL of 400 mg/kg/day for offspring and females. When the point of departure was adjusted to account for the molecular weights of the molar equivalents in the registered substance, the adjusted NOAEL was 524 mg/kg/day for Montelukast.DCHA.

Selection of the point of departure also took into account the appropriate adjustment factors to allow the derivation of the most conservative DNEL value.

Link to relevant study records

Referenceopen all close all

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD TG 421

GLP compliance:

yes

Species:

rat

Strain:

Crj: CD(SD)

Details on test animals or test system and environmental conditions:

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Details on mating procedure:

Duration of treatment / exposure:

Frequency of treatment:

once daily

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

20 mg/kg bw/day (nominal)

Dose / conc.:

40 mg/kg bw/day (nominal)

Dose / conc.:

80 mg/kg bw/day (nominal)

No. of animals per sex per dose:

12 (twelve)

Control animals:

yes, concurrent vehicle

Details on study design:

Maternal examinations:

Females (P)
(1) Clinical sign observation
Clinical sign observation was conducted on the outer body surface, nutrition status, and behavior three times a day, pre-administration, immediately post-administration, and two hours after administration. However, the observation on Saturdays and holidays occurred only pre-administration and immediately post-administration.

(2) Body weight measurement
Weight was measured between 8:30 a.m. – 12:30 p.m. during the pre-mating period before administration at one day, then at four days, eight days, 11 days, and 15 days, followed by at zero days, seven days, 14 days, and 21 days of gestation during the gestation period, followed by at zero days and four days of lactation during the lactation period.

(3) Food consumption measurement
For food consumption, the remaining food was measured between 8:30 a.m. – 12:30 p.m. on the same days that weight was measured during the pre-mating period, then at one day, seven days, 14 days, and 21 days of gestation during the gestation period, followed by at one day and four days of lactation during the lactation period, and daily food consumption was calculated from the difference from the previous day’s food consumption.

(4) Vaginal smear examination
Vaginal smears were obtained from all females during the pre-mating administration period until copulation was established and were examined microscopically. The vaginal smear images during the pre-mating administration period were classified into proestrus, estrus, postestrus, and anestrous, and the frequency of estrus stage images and the number of days from one estrus stage until the next estrus stage (estrous cycle) were examined. The presence of sperm in the vaginal smear was checked during the mating period.

(5) Delivery and nursing observations
The dams delivered naturally and the presence of any delivery abnormalities was observed. Confirmation of delivery completion was conducted every day from 21 days through 23 days and if delivery had ended by 10:30 a.m., that day was considered ‘Day 0’ of lactation. If delivery occurred after 10:30 a.m., the following day was considered ‘Day 0’ of lactation. For dams for which a completed delivery had been confirmed, they were left to care for their pups until Day 4 of lactation and their lactation condition was observed using nest building, retrieving, and lactation as the indicators.

(6) Necropsy
After the weight of all cases was measured at four days of lactation, the subjects were exsanguinated through the abdominal aorta under ether anesthesia, necropsied, the internal organs and tissue were observed macroscopically, and the number of corpora lutea and the number of implantation sites were checked. In addition, the organs and tissue in which abnormalities were observed in the necropsy were fixed in a 10% formalin solution in a phosphate buffer and preserved. The two cases (No. 4102, 4110) from the 80 mg/kg dosage group that died during gestation and the six cases from the same group (No. 4101, 4106, 4108, 4109, 4111, 4112) in which all of the pups were stillborn or all of the pups died during the lactation period were necropsied in the same manner when they were discovered.

(7) Histopathological testing
The ovaries of all cases were embedded in paraffin, segments were prepared for the control group and the high dosage group, hematoxylin-eosin staining was performed, and they were examined microscopically.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: No data
- Number of late resorptions: No data
- Other:

Fetal examinations:

1) Pup observation
At zero days of lactation, we counted the number of live born and the number of stillborn, and observed the existence of external malformations. Pups with external malformations were fixed in a 10% formalin solution in a phosphate buffer and preserved. The gender of the live born pups was determined and their weight was measured, then they were cared for by the dam. The stillborn pups were also fixed in a 10% formalin solution in a phosphate buffer and preserved.
(2) Nursling observation and measurement
Nurslings were observed once a day each day to determine whether they were alive or dead. Weight was measured at zero days (lactation Day 0) and at four days after birth. At four days after birth, all pups were exsanguinated under ether anesthesia, necropsies were performed, and the presence of internal organ abnormalities was checked.

Statistics:

Indices:

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg: salivation, unkempt fur, prone position, oligopnea, hypothermia, and poor pup retrieval

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, treatment-related

Description (incidence):

80 mg/kg: 2 females GD 21/22

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Weight gain was inhibited in the 80 mg/kg dosage group and a significant difference was observed between that group and the control group in the measurement values at four days, eight days, and 11 days, as well as at 21 days of gestation and at four days of lactation

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption in the 80 mg/kg dosage group was lower than in the control group and significant differences were observed between the two groups throughout the study

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):

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg- poor pup retrieval

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

80 mg/kg: A diaphragmatic hernia and dark red spots in the glandular stomach were observed in one case

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

control and 80 mg/kg: only the ovaries examined

Histopathological findings: neoplastic:

not examined

Number of abortions:

no effects observed

Description (incidence and severity):

see attachment

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

see attachment

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

see attachment

Early or late resorptions:

no effects observed

Description (incidence and severity):

see attachment

Dead fetuses:

effects observed, treatment-related

Description (incidence and severity):

80mg/kg live birth index = 58.5% +- 38.9

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.DescriptionIncidenceAndSeverityEffectsOnPregnancyDuration): see attachment

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
In females (P), one case died at 21 days of gestation and one died at 22 days of gestation in the 80 mg/kg dosage group. In addition, unkempt fur was recorded in the case that died at 22 days of gestation and a prone position, oligopnea, hypothermia, and poor pup retrieval were recorded in one case after delivery had been completed at 22 days of gestation. Unkempt fur and poor retrieval were observed as clinical sign changes during the lactation period in that group. Furthermore, weight gain was inhibited and low values were indicated for weight gain and food consumption in the pre-mating administration period, the gestation period, and the lactation period. However, no effects were observed in the necropsy findings or the histopathological test findings of the ovaries in that group due to administration of the test substance. No effects on clinical signs, weight, food consumption, or necropsy findings were observed in the groups with dosages of 40 mg/kg or lower.

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

dead fetuses

mortality

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg- m/f significantly lower at PND0
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): effects observed, treatment-related

Reduction in number of live offspring:

effects observed, treatment-related

Description (incidence and severity):

80mg/kg live birth index = 58.5% +- 38.9

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

effects observed, treatment-related

Description (incidence and severity):

no treatment effect on Delivery Index, body weight significantly reduced in 80mg/kg vs controls.

Changes in postnatal survival:

effects observed, treatment-related

Description (incidence and severity):

80 mg/kg viability index = 20.8% vs 99% for controls

External malformations:

no effects observed

Skeletal malformations:

not examined

Visceral malformations:

no effects observed

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Many dams with poor pup retrieval were observed during lactation in the 80 mg/kg dosage group and only four dams had surviving pups up to four days of lactation. However, lactation abnormalities were not observed in the groups with dosages of 40 mg/kg or lower. At the same time, no effects were observed on the number of dams with live born pups, the gestation rate, the number of corpora lutea, the number of implantation sites, or the implantation rate.
A significantly lower number of viable pups and a significantly lower birth rate were observed. However, no effect was observed on the number of live born pups, the number of stillborn pups, or on the gestation rate due to administration of this test substance in the groups with dosages of 40 mg/kg or lower. In addition, no effect was observed on the delivery rate in any of the groups due to administration of the test substance.
No effect was observed on the sex ratio of pups due to administration of the test substance and external malformations caused by administration of the test substance were not observed. There were many pup deaths in the 80 mg/kg dosage group during the lactation period and the viability rate in that group was remarkably low. However, no effect was observed on the viability rate of groups with dosages of 40 mg/kg or lower due to administration of the test substance. Pup weight was low for both males and females of the 80 mg/kg dosage group at zero days and four days after birth, but no effect on weight was observed in the groups with dosages of 40 mg/kg or lower due to administration of the test substance. No abnormalities thought to be caused by administration of the test substance were observed in the necropsies of the pups at four days after birth.

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reduction in number of live offspring

changes in litter size and weights

changes in postnatal survival

Abnormalities:

not specified

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

80 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects occurring together with maternal toxicity effects, but not as a secondary non-specific consequence of maternal toxicity effects

Dose response relationship:

yes

Relevant for humans:

yes

With respect to developmental toxicity:
findings which differ from controls:
low - mid - high dose versus control
---gestation index
100% - 100% - 90% versus 100%
1/10 surviving high dose dam without pups
---live birth index
99.5% - 99.0% - 58.5%(p<0.01) versus 94.9%
---viability index
99.4% - 97.8% - 20.8%(p<0.01) versus 99.0%
---body weight of pups on day 0
male: 7.0g, 6.8g, 6.1g(p<0.01) versus 7.3g
female: 6.7g, 6.5g, 5.5g(p<0.01) versus 7.0g
---body weight on day 4
male: 11.3g, 11.0g, 9.0g versus 11.8g
female: 10.6g, 10.4g, 8.6g versus 11.1g

Conclusions:

Many dams with poor pup retrieval were observed in the 80 mg/kg dosage group during lactation and effects were observed on pup survival and development due to administration of the test substance. Consequently, the reproductive development no observed effect level was determined to be 40 mg/kg/day for females, and 40 mg/kg/day for pups.

Executive summary:

A significantly lower number of viable pups and a significantly lower birth rate wereobserved. However, no effect was observed on the number of live born pups, the number of stillborn pups, or on the gestation rate due to administration of this test substance in the groups with dosages of 40 mg/kg or lower. In addition, no effect was observed on the delivery rate in any of the groups due to administration of the test substance.

Reference 2

Endpoint:: developmental toxicity
Type of information:: experimental study
Adequacy of study:: weight of evidence
Study period:: 505/11/1992- 31/03/1993
Reliability:: 2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:: comparable to guideline study with acceptable restrictions
Qualifier:: equivalent or similar to guideline
Guideline:: other: ICH S5(R2)
Deviations:: not specified
GLP compliance:: yes
Limit test:: no
Species:: rat
Strain:: Sprague-Dawley
Remarks:: Crl:CD (SD )BR
Details on test animals or test system and environmental conditions:: Source: Charles River Laboratories, Raleigh, NC; Age at Initiation: Approximately 10 weeks
Weight Range at Initiation: 214 to 298 grams

Identification Method:
Ear notches and dye markings as necessary

2. Environmental Conditions:
a. Housing:
Females were housed singly in wire mesh bottom cages;
room temperature was at 20°C to 24°C; room lights were
set with a timer for a 12-hour light and 12-hour dark cycle.

b. Diet:
The rats had free access to Purina Certified Rodent
Chow #5002 and tap water.
Route of administration:: oral: gavage
Vehicle:: CMC (carboxymethyl cellulose)
Remarks:: 0.5% aqueous
Analytical verification of doses or concentrations:: yes
Details on analytical verification of doses or concentrations:: Drug Assays and Stability:
Samples of the dosing solutions were collected during
Drug Week 1 and assayed for concentration and uniformity
and Drug Week 2 for concentration. All assays were
within acceptable limits (96.3 to 105% of desired
concentration). The compound has been shown to be
stable in this vehicle under conditions of this study.
Details on mating procedure:: Each female was housed with one untreated male of the
same strain. Females were selected for study when daily
examination revealed the presence of copulatory plugs
below the cage floor or in the vagina. The day of
finding the plug(s) was considered Day 0 of gestation.
Duration of treatment / exposure:: Days 6 through 17 of gestation.
Frequency of treatment:: Daily
Duration of test:: Until GD 21
Dose / conc.:: 50 mg/kg bw/day
Dose / conc.:: 100 mg/kg bw/day
Dose / conc.:: 400 mg/kg bw/day
No. of animals per sex per dose:: 25
Control animals:: yes, concurrent vehicle
Details on study design:: Preparation of the Test Article:
Suspensions of L-706,631 were prepared daily in the
afternoon before dosing the following day.

i. Dosing Volume:
5 ml/kg based on most recent body weight
Maternal examinations:: Physical Signs:
Females were observed for physical signs once daily on
Day 0 and during Days 6 through 21 of gestation and
additionally at one to five hours after the dosing on Days 6
through 17 of gestation.

Maternal Body Weights:
Recorded on Days 0, 6, 8, 10, 12, 14, 16, 18, and 21 of
gestation.

Food Consumption:
Measured for all animals on Days 3 to 5, 6 to 8, 9 to 11, 12
to 14, 15 to 17, and 18 to 20 of gestation.

Necropsy:
A gross examination of thoracic and abdominal viscera was
done on all sacrificed F0 females.
Ovaries and uterine content:: Sacrifice and Reproductive Status:
All females were euthanized on Day 21 of gestation by CO2
asphyxiation. The uterus of each female was examined to
determine reproductive status (pregnant or non-pregnant).
The number of corpora lutea were counted.
Fetal examinations:: Females sacrificed on Day 21 of gestation were assigned a
code number so that litters could be examined without
knowledge of treatment group. The order of examination was
determined by a computer-generated list of random
permutations of 4. Implants were counted, classified as
live fetus, dead fetus, or resorption. All fetuses were
weighed and examined externally. Every third fetus in each
litter and externally malformed fetuses as deemed
appropriate were given a visceral examination by
dissection. The heads of these fetuses were fixed in
Bouin's solution and later examined by free-hand coronal
sections. All fetuses were fixed, cleared, and stained with
alizarin red for subsequent skeletal examination.
Statistics:: Statistical analyses were based on analysis of variance
using a least significant difference procedure after
normalizing for nonparametric data by a rankit method. A
trend analysis was used to determine if there was a
significant trend with increasing dosage. If there was a
statistically significant trend, data from the high dose
group were excluded and the trend repeated until a
no-statistical-analysis-of-trend dose was identified.

Results were considered to be statistically significant if
P < 0.05.
Indices:: a. Maternal body weight changes between Days 6 and 18, 18
and 21 (adjusted for Day 6 body weight where
appropriate).
b. Implants/pregnant female
c. (resorptions + dead fetuses)/implants (litter mean)
d. Live fetuses/pregnant female
e. Live fetal weight (litter mean) males and females
separated (adjusted for time to sacrifice and/or litter
size where appropriate)
Clinical signs:: no effects observed
Dermal irritation (if dermal study):: not examined
Mortality:: mortality observed, non-treatment-related
Description (incidence):: one female assigned to the 100 mg/kg bw/day group found dead on Day 0
Body weight and weight changes:: effects observed, non-treatment-related
Description (incidence and severity):: From Gestational Days 6 to 18, there were significant
(P s 0.05) non-dose-related decreases in maternal body
weight gain of 15.7, 11.8, and 7.8% below control in the 50,
100, and 400 mg/kg/day dose groups, respectively, as
compared to controls. These decreases are not considered
related to treatment.
Food consumption and compound intake (if feeding study):: no effects observed
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:: no effects observed
Neuropathological findings:: not examined
Histopathological findings: non-neoplastic:: not examined
Histopathological findings: neoplastic:: not examined
Details on results:: 1. Mortality and Abortions:
There were no treatment-related deaths or abortions.
One female (#92-4772) assigned to the 100 mg/kg/day group
was found dead on Day 0 of gestation prior to initiation of
dosing and was replaced.

Physical Signs:
There were no treatment-related physical signs.

Maternal Body Weight Changes (Figure 1: Tables 1, 2, and 9):
From Gestational Days 6 to 18, there were significant
(P s 0.05) non-dose-related decreases in maternal body
weight gain of 15.7, 11.8, and 7.8% below control in the 50,
100, and 400 mg/kg/day dose groups, respectively, as
compared to controls. These decreases are not considered
related to treatment. Similar decreases in body weight were
not observed in the oral range-finding reproduction study in
rats (TT #92-717-1) at doses of 50 or 100 mg/kg/day and no
treatment-related maternal body weight changes occurred
during gestation in the oral female fertility study
(TT #92-723-0) at doses of 50, 100, and 200 mg/kg/day
indicating a lack of maternal toxicity. In the
above-mentioned female fertility study, there were
transiently decreased weight gains in the 14-day premating,
as in the present study, in the initial weeks of drug
administration; however, similar decreases have generally
not been observed in oral toxicity studies in rats at these
doses upon administration of L-706,631.

Food Consumption (Figure 2: Tables 3 and 10):
There were no treatment-related effects on average
maternal food consumption.

Gross Necropsy (Appendix II):
There were no treatment-related gross lesions seen at
necropsy of F0 females.
Number of abortions:: no effects observed
Pre- and post-implantation loss:: effects observed, non-treatment-related
Description (incidence and severity):: Pre-implant loss: (litter mean)
0mg/kg: 5.9%; 50mg/kg: 10.8%; 100mg/kg: 13.1%; 400 mg/kg: 10.4%

post implant loss: %(resorptions+dead fetus)/implant (litter mean)
0mg/kg: 3.8%; 50mg/kg: 8%; 100mg/kg: 10.3%; 400 mg/kg: 6.6%
Total litter losses by resorption:: effects observed, non-treatment-related
Description (incidence and severity):: observed in 1 dam per dose group excluding control
Early or late resorptions:: not specified
Dead fetuses:: effects observed, non-treatment-related
Description (incidence and severity):: 50 mg/kg: incidnece of 2 dead fetus
100mg/kg: incidnec eof 1 dead fetus
Changes in pregnancy duration:: no effects observed
Description (incidence and severity):: Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed
Changes in number of pregnant:: effects observed, non-treatment-related
Description (incidence and severity):: one female in each of the control and 50 mg/kg goups failed to fall pregnant
Details on maternal toxic effects:: NO maternal toxicity observed
: Key result
Dose descriptor:: NOAEL
Effect level:: 400 mg/kg bw/day
Based on:: test mat.
Basis for effect level:: other: There was no treatment-related evidence of maternal or fetal toxicity observed at oral doses of up to 400 mg/kg/day.
Fetal body weight changes:: no effects observed
Description (incidence and severity):: Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): 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:: not examined
External malformations:: effects observed, non-treatment-related
Description (incidence and severity):: 2 fetus in the 50 mg/kg group: anopthalmia (1) and cleft palete (1)
Skeletal malformations:: effects observed, non-treatment-related
Description (incidence and severity):: cervical vertebra: 400 mg/kg (1 animal)
Thoracic vertebra: 0mg/kg (1 animal)
Hypoplastic rib: 0mg/kg (2 animals); 50 mg/kg (3 animals); 100 mg/kg (4 animals); 400 mg/kg (1 animal)
Visceral malformations:: effects observed, non-treatment-related
Description (incidence and severity):: Hydroureter: 100 mg/kg (2 animals)
Details on embryotoxic / teratogenic effects:: Embryo Survival (Tables 4 and 11):

There were no treatment-related effects. There were
increases in percent preimplantation loss in all dose groups
as compared to controls without significant effects on the
number of implants or live fetuses per litter or percent
(resorptions dead fetuses)/implant (litter mean). The
increase in percent preimplantation loss can be accounted
for by the following one or two litters per group which had
few implants or totally resorbed litters: (#92-4725,
92-4745, 50 mg/kg/day group; #92-4750, 92-4770,
100 mg/kg/day group; #92-4797, 400 mg/kg/day group). As
treatment in this study was initiated post-implantation and
there were no increases in percent preimplantation loss in
the female fertility study (TT #92-723-0), these increases
are not considered treatment related. Similar litters with
large numbers of resorptions or few implants are observed
occasionally in historical control groups.

Live Fetal Weight (Tables 4. 11. and 12):
There were no effects on live fetal weight.

Fetal Examinations (Tables 4. 5. 6. 7. 8. 11. and 12):
There were no treatment-related effects on fetuses based
on external, visceral, or skeletal examination. There was a
slight non-dose-related increase in numbers of fetuses with
supernumerary ribs of 15, 14, and 11% (litter mean) in the
50, 100, 400 mg/kg/day groups, respectively, compared to
7.7% in controls. The overall incidence of supernumerary
ribs for historical controls in our laboratory is 18.1% of
total fetuses so that the apparent increase in treated
groups really reflects a low concurrent control value.
These slight increases in numbers of supernumerary ribs
relative to concurrent controls are not considered
treatment related.
: Key result
Dose descriptor:: NOAEL
Effect level:: 400 mg/kg bw/day
Based on:: test mat.
Sex:: male/female
Basis for effect level:: other: There was no treatment-related evidence of maternal or fetal toxicity observed at oral doses of up to 400 mg/kg/day.
: Key result
Developmental effects observed:: no
Lowest effective dose / conc.:: 400 mg/kg bw/day
Treatment related:: no
Conclusions:: here was no treatment-related evidence of maternal or fetal
toxicity observed at oral doses of up to 400 mg/kg/day.
Non-dose-related, but significant (P s 0.05), decreased maternal
body weight gains during gestation were not considered treatment
related due to the lack of a dose-response and the absence of
similar effects in other rat studies with L-706,631 which
included treatment during gestation.
The no-treatment-related-effect dose for maternal and
developmental toxicity is 400 mg/kg/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:: adverse effect observed
Dose descriptor:: NOAEL
: 169.2 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

Justification for classification or non-classification

The registered substance comprises of two component ions which can be expected to dissociate into their respective species following oral administration and exposure to gastric fluids. The chemical species have been examined in separate reproductive screening studies which resulted in NOAEL of 40 mg/kg bw/day and 100 mg/kg bw/day for DCHA and sodium montelukast respectively.

The toxic effects of DCHA upon reproductive indices (significant changes to still births, live birth index, viability index and mean pup body weight) were observed with concomitant Maternal Toxicity. Taken in conjunction with the known effects of DCHA upon the functioning of the sympathetic nervous system in the 28 day repeat dose study, at similar doses to those administered in the reproductive screening study; it is highly likely that any pup mortality observed was as a result of systemic toxicity rather than any reproduction specific mechanism.

Maternal toxicity in P0 females treated with 200 mg/kg bw/day Montelukast sodium (significant decrease in bodyweight of 23% compared to controls) is likely to have contributed to the slight decreases in fertility and fecundity and the reduced F1 pup birth weight observed. No other signficant adverse effects were noted for the F1 or F2 generations in any of the reproductive or developmental indices.

Based upon the observed reproductive effects of the constituent substances in theregistered substance, there is insufficient evidence to propose a classification for Reproductive Toxicity in accordance with the criteria set out in 1272/2008/EC.

Additional information

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Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

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Registration Dossier

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Diss Factsheets

N-cyclohexylcyclohexanamine 2-[1-[[[(1R)-1-[3-[(1E)-2-(7-chloroquinolin-2-yl)ethenyl]phenyl]-3-[2-(2-hydroxypropan-2-yl)phenyl]propyl]sulfanyl]methyl]cyclopropyl]acetate

Endpoint summary

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

Link to relevant study records

Referenceopen allclose all

Reference 1

Reference 2

Effect on fertility: via oral route

Effect on fertility: via inhalation route

Effect on fertility: via dermal route

Effects on developmental toxicity

Description of key information

Link to relevant study records

Referenceopen allclose all

Reference 1

Reference 2

Effect on developmental toxicity: via oral route

Effect on developmental toxicity: via inhalation route

Effect on developmental toxicity: via dermal route

Justification for classification or non-classification

Additional information

Referenceopen all close all

Referenceopen all close all