Cyclohexyldimethylamine

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

There was no evidence for effects on reproduction in the OECD 422 screening study.

Link to relevant study records

Reference

Endpoint:

toxicity to reproduction

Remarks:

other: Repproductive toxicity/fertility and developmental toxicity Screening test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

IN-LIFE DATES: From: September 30th, 2009 To: December 7th, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was carried out according to OECD guideline 422 and is GLP compliant.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Crl:WI(Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: Approximately 12 weeks
- Weight at study initiation: Males: 297 - 303 g; Females: 200 - 204 g
- Fasting period before study: Not applicable
- Housing: Housed in a controlled environment in Macrolon cages (MIV type, height 18cm). Animals were housed in groups of 5 animals/sex/cage during the pre-mating period. During the mating period, females were caged together with males on a one-to-one-basis in Macrolon (type MIII) cages. Post-mating, males were housed in their home cage (MIV type) with a maximum of 5 animals/cage. Females were individually housed in Macrolon cages (MIII type). Sterilised sawdust was used as bedding material and paper as cage enrichment.
- Diet (e.g. ad libitum): Free access to prepared diets, Standard powder rodent diet (SM R/M-Z fromSSNIFF® Spezialdiäten GmbH, Soest, Germany)
- Water (e.g. ad libitum): Free access to tap-water
- Acclimation period: At least 5 days prior to start of treatment.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3°C (actual range: 20.1 – 21.8°C)
- Humidity (%): 40 - 70% (actual range: 32 - 100%)
- Air changes (per hr): 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours artificial light and 12 hours darkness per day


IN-LIFE DATES: From: September 30th, 2009 To: December 7th, 2009

Route of administration:

oral: feed

Type of inhalation exposure (if applicable):

other: Not applicable

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was mixed without the use of a vehicle, directly with some powder feed (premix) and subsequently mixed with the bulk of the diet. Water (approximately 15% in total) was added to aid pelleting. The pellets were dried for approximately 24 hours at 35°C before storage. The control animals received similarly prepared pellets but without the test substance.

DIET PREPARATION
- Rate of preparation of diet (frequency): Diets were prepared once weekly
- Mixing appropriate amounts with (Type of food): powder feed (premix) and subsequently mixed with the bulk of the diet.
- Storage temperature of food: Kept at room temperature in the diet store room

Details on mating procedure:

Following a minimum of 14 days of exposure for the males and females, one female was cohabited with one male of the same treatment group, avoiding sibling mating (Charles River supplied non-litter mates). Detection of mating was confirmed by evidence of sperm in the vaginal lavage, by staging of the oestrus cycle and/or by the appearance of an intravaginal copulatory plug. This day was designated Day 0 post-coitum. Once mating had occurred, the males and females were separated. A maximum of 13 days was allowed for mating. After 13 days of mating, females who had not shown
evidence of mating were separated from their males.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Accuracy, homogeneity and stability were determined for diets prepared for use during treatment.
For determination of accuracy, samples were taken at random position or at 90%, 50% and 10% height. The latter set of samples was also used for the determination of the homogeneity of the diets. For determination of stability, additional samples were taken at 50% height and stored at room temperature for 2 weeks or 8 days. Analyses were performed on samples taken in week 4 and week 7. Analysis was carried out using LC-MS/MS.

Duration of treatment / exposure:

Males were exposed for 28 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 41-54 days, i.e. during 2 weeks prior to mating, during mating, during post-coitum, and during at least 5 days of lactation.

Frequency of treatment:

Ad libitum for at least 28 days. Animals received test diet from Day 1 until the day prior to necropsy.

Details on study schedule:

- Age at mating of the mated animals in the study: approximately 14 weeks

Dose / conc.:

0 ppm (nominal)

Remarks:

nominal in diet

Dose / conc.:

150 ppm (nominal)

Remarks:

nominal in diet

Dose / conc.:

500 ppm (nominal)

Remarks:

nominal in diet

Dose / conc.:

1 500 ppm (nominal)

Remarks:

nominal in diet

No. of animals per sex per dose:

5 animals/sex/dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: The dietary inclusion levels were based on the results of the dose range finding study. Rats were exposed to 500, 1500 and 5000 ppm. At 5000 ppm, severe reduction in food consumption, body weight loss and hunched posture were reported. At 500 and 1500 ppm, reduction in food consumptionwith slight receovery was noted. On this basis, 1500 ppm was selected as the highest dose to be tested.

Positive control:

Not applicable

Parental animals: Observations and examinations:

MORTALITY/VIABILITY: Yes
- Time schedule: At least twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once daily (Observations were also made outside the cage prior to start treatment and at weekly intervals thereafter)

BODY WEIGHT: Yes
- Time schedule for examinations: on the first day of exposure and weekly thereafter. Mated females were weighed on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum, and during lactation on days 1 and 4.

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, weekly for males and females. During the mating period, food consumption in males was recorded on Days 1, 8 and 14. After mating, food consumption in males was recorded on days 8 and 14. Food consumption of mated females was measured on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and on days 1 and 4 of lactation. non-mated females, food consumption was recorded at least once weekly manually after completion of the mating period until necropsy.
- Compound intake: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes, subjective appraisal was performed during the study.

OPHTHALMOSCOPIC EXAMINATION: Not performed as it is not required in the OECD guideline 422

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Taken prior to necropsy
- Anaesthetic used for blood collection: Yes (iso-flurane)
- Animals fasted: Yes, animals were fasted overnight
- How many animals: 5 animals/sex/dose group
- Parameters checked: Haematology: White blood cells, differential leucocyte count (neutrophils, lymphocytes, monocytes, eosinophils, basophils), red blood cells, reticulocytes, red blood cell distribution width, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelets, Clotting Potential: Prothrombin time, activated Partial thromboplastin time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood:
- Animals fasted: Yes, animals were fasted overnight
- How many animals: 5 animals/sex/dose group
- Parameters checked: Clinical Biochemistry: Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total protein, albumin, total bilirubin, urea, creatinine, glucose, cholesterol, sodium, potassium, chloride, calcium, inorganic phosphate, bile acids

URINALYSIS: Not performed since it is not mandatory according to OECD guideline 422.

NEUROBEHAVIOURAL EXAMINATION: Yes,
- Time schedule for examinations: 5 males/ dose group were tested during Week 4 of treatment and 5 females/dose group were tested during lactation
- Dose groups that were examined:All dose groups
- Battery of functions tested: sensory activity / grip strength / motor activity / other: hearing ability, pupillary reflex, static righting reflex and grip strength, motor activity

Oestrous cyclicity (parental animals):

No specific information is available on the oestrus cycle

Sperm parameters (parental animals):

Parameters examined in male parental generations:
testis weight, epididymides weight, examination of staging of spermatogenesis.

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number of dead and living pups at first litter check, sex ratio, postnatal loss, viability index, body weights,
early postnatal pup development (mortality and clinical signs)

GROSS EXAMINATION OF DEAD PUPS:
Gross external necropsy. Descriptions of all external abnormalities were recorded. The stomach was examined for the presence of milk. If possible, defects or cause of death were evaluated.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals following completion of the mating period (a minimum of 28 days of dose administration).
- Maternal animals: All surviving females which delivered were killed on lactation Days 5-7. All surviving females which failed to deliver were killed
post-coitum on Day 26 (female no. 49, with evidence of mating) and 21 days after the last day of the mating period (female nos. 45 and 74, without evidence of mating).

GROSS PATHOLOGY: Yes, 5 animals/ sex/group
All animals were subjected to macroscopic examination of the cranial, thoracic and abdominal tissues and organs, with special attention being paid to the reproductive organs.

The following organs were examined with the exception of the tissues/organ in parentheses for which no signs of toxicity were noted at macroscopic examination.

Identification marks: not processed
Adrenal glands
Aorta
Brain (cerebellum, mid-brain, cortex)
Caecum P
Cervix
Clitoral gland
Colon
Duodenum
Epididymides
Eyes with optic nerve (if detectable) and
Harderian gland
(Female mammary gland area) Spinal cord -cervical, midthoracic, lumbar
Femur including joint
Heart
Ileum
Jejunum
Kidneys
(Larynx)
(Lacrimal gland, exorbital)
Liver
Lung, infused with formalin
Lymph nodes - mandibular, mesenteric
(Nasopharynx)
Oesophagus
Ovaries
Pancreas
Peyer's patches (jejunum, ileum) if detectable
Pituitary gland
Preputial gland
Prostate gland
Rectum
(Salivary glands - mandibular, sublingual)
Sciatic nerve
Seminal vesicles including coagulating glands
Skeletal muscle
(Skin)
Spinal cord -cervical, midthoracic, lumbar
Spleen
Sternum with bone marrow
Stomach
Testes
Thymus
Thyroid including parathyroid (if detectable)
(Tongue)
Trachea
Urinary bladder
Uterus
Vagina
All gross lesions

All remaining animals and females which failed to deliver:
Cervix
Clitoral gland
Coagulation gland
Epididymides
Ovaries
Preputial gland
Identification marks: not processed
Prostate gland
Seminal vesicles
Testes
Uterus
Vagina
All gross lesions

HISTOPATHOLOGY: Yes
All organ and tissue samples, as defined under Histopathology (following), were processed, embedded and cut at a thickness of 2-4 micrometers and stained with haematoxylin and eosin (Klinipath, Duiven, The Netherlands) in 5 males from the control and high dose group. Additional slides of the testes of 5 males of group 1 and 4 were also examined. All gross lesions of all dose groups and the reproductive organs of all animals that failed to mate, conceive, sire or deliver healthy pups were also studied.

Postmortem examinations (offspring):

SACRIFICE
- These animals were subjected to postmortem examinations (macroscopic examination).

All pups were sexed and descriptions of all external abnormalities were recorded. The stomach was examined for the presence of milk. If possible, defects or cause of death were evaluated.

Statistics:

The following statistical methods were used to analyse the data:
- If the variables could be assumed to follow a normal distribution, the Dunnett-test (Dunnett, 1955) (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
- The Steel-test (Miller, 1981) (many-to-one rank test) was applied if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test (Fisher, 1950) was applied to frequency data.
The number of corpora lutea was transformed by using 1/x to obtain a normal distribution. This was followed by ANOVA. The Dunnett-test (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control group.
The number of implantation sites was subjected to the Kruskal-Wallis nonparametric ANOVA test (Kruskal, 1952) to determine intergroup difference. If the results of the ANOVA were significant (p<0.05), the Wilcoxon test (Wilcoxon, 1945) was applied to the data to compare the treated groups to the control group.
All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance.
Test statistics were calculated on the basis of exact values for means and pooled variances.
Individual values, means and standard deviations may have been rounded off before printing.
Therefore, two groups may display the same printed means for a given parameter, yet display
different test statistics values.
No statistical analysis was performed on histopathology findings.

Reproductive indices:

The following parameters were analysed:
percentage mating males, percentage mating females, fertility index males, fertility index females, conception rate, gestation index, duration of gestation

Offspring viability indices:

The following parameters were analysed:
percentage live males at first litter check, percentage live females at first litter check, percentage of post-natal loss days (0-4) of lactation, viability index

Clinical signs:

no effects observed

Description (incidence and severity):

see results below

Body weight and weight changes:

no effects observed

Description (incidence and severity):

see results below

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

see results below

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

see results below

Other effects:

no effects observed

Description (incidence and severity):

Test substance intake: see results below

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Description (incidence and severity):

see results below

CLINICAL SIGNS AND MORTALITY
No mortality occurred during the study period.
No clinical signs of toxicity were noted during the observation period.
Slight alopecia was noted for one female rat of Group 1. This finding occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study.

BODY WEIGHT AND WEIGHT GAIN
Body weight and body weight gain was reduced for males and females on Day 8 prior to mating in the 1500 ppm dose group. This was considered to be related to the decreased food consumption in these animals on Days 1-8. Body weights and body weight gain remained lower in these animals
during the mating period; however when body weight gain was calculated from Day 8 onwards no difference was noted compared to the control group.
In females treated at 500 and 1500 ppm decreased body weights and body weight gain (not
always statistically significant) were noted during the post-coitum phase. However, the decrease was not always statisticalyl significant. In these females, body weights were also reduced during the lactation phase.

Terminal body weight was significantly lower in males at 1500 ppm and females at 500 and 1500 ppm when compared to control animals.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
Food consumption (absolute and relative) was lower for males and females treated at 1500 ppm over Days 1-8 premating, with recovery of food consumption after Day 8. Slightly reduced food consumption was also noted for females treated at 1500 ppm on several occasions post-coitum, and during lactation. Minor statistically significant differences arising between controls and females receiving 150 or 500 ppm during post-coitum were considered not to represent a change of biological significance.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
No abnormalities were seen in the reproductive organs of suspected non-fertile animals which could account for infertility. The assessment of the integrity of the spermatogenetic cycle did not provide any evidence of impaired spermatogenesis. Percentage mating, fertility index, conception rate, precoital time, and number of corpora lutea and implantation sites were unaffected by treatment. No toxicologically significant effects on reproductive parameters were noted.

ORGAN WEIGHTS (PARENTAL ANIMALS)
No changes were deemed to be due to DMCHA
The following statistically significant changes in organ weights distinguished treated from control
animals:
- Decreased absolute prostate weights at 1500 ppm
- Decreased absolute and relative seminal vesicles weights at 1500 ppm
- Decreased absolute thymus weights for females at 500 and 1500 ppm
- Decreased absolute adrenals weights for females at 1500 ppm
- Decreased absolute spleen weights for females at 1500 ppm
In the absence of any corroborative microscopic findings, these changes were considered to be of no toxicological significance.

High weights for liver and kidneys and low weight for the testes were recorded in one male in the 1500 ppm dose group. These findings were in line with the enlarged liver and kidneys and reduced size of the testes.

Increased relative brain weights in males in the 1500 ppm dose group and in females in the 500 and 1500 ppm dose group were not deemed to be of toxicological relevance.

The statistical significant changes noted for w eights of ovaries and uteri were considered to be caused by the relatively high control value. All other statistical significant changes (thyroids of males at 150 and 500 ppm and spleen of females at 500 ppm) were in the normal range of biological variation noted for rats of this strain and age. In the absence of a dose-response relationship, they were considered to be of no toxicological significance.

GROSS PATHOLOGY (PARENTAL ANIMALS)
No macroscopic changes at necropsy were deemed to be treatment related. Changes such as enlarged liver and kidneys, pelvic dilation and pale discolouration of the kidneys and reduced size of the testes were reported in one male in the 1500 ppm dose group. One female in the 150 ppm dose group showed an enlarged spleen and a soft red-brown nodule in the subcutis of the genital region. Incidental findings were also noted however these findings were within the historical control range among rats of this age and strain.

HISTOPATHOLOGY (PARENTAL ANIMALS)
One female in the 150 ppm dose group displayed a mammary gland adenocarcinoma. However, this is a common finding in this strain of rats of this age.

OTHER FINDINGS (PARENTAL ANIMALS)

Key result

Dose descriptor:

NOAEL

Effect level:

> 1 500 ppm

Sex:

male/female

Basis for effect level:

other: No systemic toxicity was observed at 1500 ppm (the highest dose level tested)

Clinical signs:

no effects observed

Description (incidence and severity):

see results below

Mortality / viability:

no mortality observed

Description (incidence and severity):

see results below

Body weight and weight changes:

no effects observed

Description (incidence and severity):

see results below

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

see results below

Histopathological findings:

not examined

VIABILITY (OFFSPRING)
Gestation index, duration of gestation, number of dead and living pups at first litter check, sex ratio, postnatal loss, viability index, and early postnatal pup development (mortality, clinical signs and external macroscopy) were unaffected by treatment.

CLINICAL SIGNS (OFFSPRING)
Incidental clinical symptoms op pups consisted of small size, blue spot on the nose, and cold appearance.

BODY WEIGHT (OFFSPRING)
Body weights of pups were slightly decreased at 500 and 1500 ppm on Days 1 and 4 of lactation.

GROSS PATHOLOGY (OFFSPRING)
Macroscopic examination revealed autolysis for one pup that was found dead at first litter check, and small size was noted for a few pups. No relationship with treatment was established for these observations and they were considered to be of no toxicological significance.

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 500 ppm

Based on:

test mat.

Sex:

male/female

Remarks on result:

not measured/tested

Key result

Critical effects observed:

no

Reproductive effects observed:

not specified

Reproduction Data F0-generation.                Group 1    Group 2    Group 3     Group 4

                                                        Control 150 PPM       500 PPM    1500 PPM

Paired Males                                          10          10               10                10

Mated Males                                           9           10               10                 9

Males generating a pregnancy                      8           10               10                 9

Paired Females                                       10          10               10                10

Mated Females                                         9           10              10                  9

Non-pregnant Females                                 1            0                 0                 0

Pregnant Females                                      8           10               10                  9

Number of litters with living pups on Day 1          8           10               10                  9

 

 

	Group 1 control	Group 2 150 ppm	Group 3 500 ppm	Group 4 1500 ppm
Percentage mating (Males)  (Males mated / Males paired) * 100	90.0	100	100	90.0
Fertility index (Males) (Males generating a pregnancy / Males paired) * 100	80.0	100	100	90.0
Percentage mating (Females) (Females mated / Females paired) * 100	90.0	100	100	90.0
Fertility index (Females) (Females achieving a pregnancy / Females paired) * 100	80.0	100	100	90.0
Conception rate (Females achieving a pregnancy / Females mated) * 100	88.9	100	100	100
Gestation index (Number of females with living pups / Number of females pregnant) * 100	100	100	100	100

 

Conclusions:

Further to the administration of DMCHA, changes in in body weights were reported. However, these changes were within the historical control and were therefore not deemed to be treatment related. No changes for reproductive parameters were revealed. On this basis, the the following No Observed Adverse Effect Levels (NOAEL) were derived parental NOAEL at least 1500 ppm (equivalent to 91-104 mg DMCHA/kg bw in males and 85-147 mg DMCHA/kg bw in females) , reproductive NOAEL at least 1500 ppm(equivalent to 91-104 mg DMCHA/kg bw in males and 85-147 mg DMCHA/kg bw in females) and developmental NOAEL at least 1500 ppm (equivalent to 91-104 mg DMCHA/kg bw in males and 85-147 mg DMCHA/kg bw in females)

Executive summary:

Four groups of ten Wistar Han rats/sex were exposed to cyclohexyldimethylamine (DMCHA) by dietary administration at the following dose levels: 0, 150, 500 and 1500 ppm. Males received the test substance for 28 days (2 weeks prior to mating, during mating and up to necropsy). Females were exposed for 41 -54 days (2 weeks prior to mating, during mating, during post-coitum and during at least 4 days of lactation). Clinical signs, functional observations, body weights, food consumption, reproduction parameters, observation of pups, clinical pathology, macroscopy, organ weights, and histopathology were evaluated. Chemical analyses of diet were conducted twice during the study to assess accuracy, homogeneity and stability. The diet was homogeneous and stable for at least 8 days at room temperature. Decreased body weights and food consumption were reported at 1500 ppm in males and females during week 1. This change was attributed to a palatability effect of the compound. After week 1, food consumption increased to normal values and body weight gain was normal compared to the control group. Other effects on body weights were noted in females mainly during the postcoitum phase; this decrease could not be solely explained by the food consumption in these animals. One male in the 1500 ppm dose group showed slight centrilobular hepatocellular liver hypertrophy, marked, bilateral, progressive nephropathy and slight vacuolation of the zona fasciculata of the adrenal glands together with several changes for clinical biochemistry parameters, macroscopic findings and organ weight changes. As these findings were not noted in the remaining animals of this dose group, it was not deemed to be treatment related. No treatment-related changes were noted in any of the parameters studied (i.e. clinical appearance, functional observations, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). No parental effects were observed at 150 ppm. No reproductive effects were observed at any dose level. Decrease in body weights in pups were reported in the 500 and 1500 ppm dose group, which are at the same dose levels as effects on maternal body weight were noted. No other developmental effects were observed at 500 and 1500 ppm. No treatment-related changes were noted in any of the developmental parameters studied (i.e. gestation index, duration of gestation, number of dead and living pups at first litter check, sex ratio, postnatal loss, viability index, and early postnatal pup development (mortality, clinical signs and external macroscopy)). No developmental effects were observed at 150 ppm. Changes in bodyweight and food consumption at 500 ppm and 1500 ppm were not deemed to be due to DMCHA. Based on the absence of treatment related effects, the No-Observed Adverse Effect Level is greater than 1500 ppm.   Based on these results, the test substance does not require classification according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.

Effect on fertility: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

85 mg/kg bw/day

Additional information

In a study conducted by van Tuyl (2010), four groups of ten Wistar Han rats/sex were exposed to cyclohexyldimethylamine (DMCHA) by dietary administration at the following dose levels: 0, 150, 500 and 1500 ppm. Males received the test substance for 28 days (2 weeks prior to mating, during mating and up to necropsy). Females were exposed for 41 -54 days (2 weeks prior to mating, during mating, during post-coitum and during at least 4 days of lactation). Clinical signs, functional observations, body weights, food consumption, reproduction parameters, observations pups, clinical pathology, macroscopy, organ weights, and histopathology were evaluated. Chemical analyses of diet were conducted twice during the study to assess accuracy, homogeneity and stability. The diet was homogeneous and stable for at least 8 days at room temperature. Decreased body weights and food consumption were reported at 1500 ppm in males and females during week 1. This change was attributed to a palatability effect of the compound. After week 1, food consumption increased to normal values and body weight gain was normal compared to the control group. Other effects on body weights were noted in females mainly during the postcoitum phase; this decrease could not be solely explained by the food consumption in these animals. One male in the 1500 ppm dose group showed slight centrilobular hepatocellular liver hypertrophy, marked, bilateral, progressive nephropathy and slight vacuolation of the zona fasciculata of the adrenal glands together with several changes for clinical biochemistry parameters, macroscopic findings and organ weight changes. As these findings were not noted in the remaining animals of this dose group, it was not deemed to be treatment related. No treatment-related changes were noted in any of the parameters studied (i.e. clinical appearance, functional observations, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). No parental effects were observed at 150 ppm. No reproductive effects were observed at any dose level. Decrease in body weights in pups were reported in the 500 and 1500 ppm dose group, which are at the same dose levels as effects on maternal body weight were noted. No other developmental effects were observed at 500 and 1500 ppm. No treatment-related changes were noted in any of the developmental parameters studied (i.e. gestation index, duration of gestation, number of dead and living pups at first litter check, sex ratio, postnatal loss, viability index, and early postnatal pup development (mortality, clinical signs and external macroscopy)). No developmental effects were observed at 150 ppm. Changes in bodyweight and food consumption at 500 ppm and 1500 ppm were not deemed to be due to DMCHA. Based on the absence of treatment related effects, the No-Observed Adverse Effect Level is greater than 1500 ppm, equivalent to 91 to 104 mg/kg bw/day for males and 85 to 147 mg/kg bw/day for females.   Based on these results, the test substance does not require classification according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.

Based on the absence of reproductive effects in the reproductive/developmental screening test it is not scientifically justified to carry out a two generation study. There is sufficient evidence that shows that DMCHA is corrosive. At low dose levels mild effects are noted such as reduction in food consumption associated with body weight loss in the first week indicates that the test substance is not palatable. There are no effects on reproduction in the screening test. Therefore a two generation study will not provide any additional information on reproductive effects.

Effects on developmental toxicity

Description of key information

There was no evidence for developmental toxicity in a guideline (OECD 414) oral study conducted in the rat.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 November 2015 to 11 July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

January 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

Version / remarks:

August 1998

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries Testing guidelines for Toxicology studies, 12 NohSan No 8147

Version / remarks:

November 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Dimethylcyclohexylamine Batch No.: 1920179, obtained from Air Products and Chemicals, Inc. USA
- Expiration date of the lot/batch: 02/02/2018
- Purity test date: 99.3% w/w tested on 02/02/2015

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark; prepared dosing formulations were stored at 4°C in the dark
- Stability under test conditions: assumed stable for the duration of the study
- Solubility and stability of the test substance in the solvent/vehicle: stable in the vehicle (Arachis oil BP) for 14 days (determined during a previous study)

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD (SD) IGS BR

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited, Margate, Kent.
- Age at study initiation: adult females, delivered prior to Day 3 of gestation
- Weight at study initiation: 201 - 308 g
- Fasting period before study: None
- Housing: individually in solid-floor polypropylene cages with stainless steel mesh lids furnished with softwood flakes with environmental enrichment (wooden chew blocks and cardboard fun tunnels)
- Diet (e.g. ad libitum): Rodent 2018C Teklad Global Certified Diet, Envigo RMS (UK) Limited, Oxon, UK), ad libitum
- Water (e.g. ad libitum): mains drinking water ad libitum
- Acclimation period: none

DETAILS OF FOOD AND WATER QUALITY: The diet, drinking water bedding and environmental enrichment were considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study. Certificates of analysis of the batches of diet used are available.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12 hour light/dark cycle (low intensity fluorescent lighting)

IN-LIFE DATES: From: 22 January 2016 To: 10 February 2016

Route of administration:

oral: gavage

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: formulations were prepared in two batches and stored at ~4°C in the dark.

VEHICLE
- Justification for use and choice of vehicle (if other than water): arachis oil BP was chosen based on previous studies
- Concentration in vehicle: 0, 2.5, 12.5, 25 mg/mL
- Amount of vehicle (if gavage): dose volumes were maintained at 4 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples were taken of each test item formulation and were analyzed for concentration of Dimethylcyclohexylamine at Envigo Analytical Laboratory, Shardlow. The method used for analysis of formulations was GC using FID detection. The results indicated that the prepared formulations were within 90-109% of the nominal concentration and were considered to be acceptable for the purposes of the study.

Details on mating procedure:

Confirmed-pregnant (prior to GD3) animals were obtained from the supplier

Duration of treatment / exposure:

From Day 3 to Day 19 of gestation, inlcusive

Frequency of treatment:

Once daily

Duration of test:

From Day 3 to Day 19 of gestation

Dose / conc.:

0 mg/kg bw/day

Remarks:

vehicle control

Dose / conc.:

10 mg/kg bw/day

Dose / conc.:

30 mg/kg bw/day

Dose / conc.:

100 mg/kg bw/day

No. of animals per sex per dose:

24 females/dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were chosen based on previous toxicity data
- Rationale for animal assignment: animals were randomly allocated to treatment groups using a randomization procedure based on stratified body weight

Maternal examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: observations were recorded immediately before and soon after dosing and one hour post dosing, and following arrival and once daily during gestation.

BODY WEIGHT: Yes
- Time schedule for examinations: Individual body weights were recorded on Day 3 (before the start of treatment) and on Days 4, 5, 8, 11, 14 and 17 of gestation. Body weights were also recorded for animals at terminal kill (Day 20).

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined: Yes
- Time schedule for examinations: Food consumption was recorded for each individual animal at Day 3, 5, 8, 11, 14, 17 and 20 of gestation.

WATER CONSUMPTION: Yes
- Time schedule for examinations: Water intake was observed daily by visual inspection of the water bottles for any overt changes.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20; all animals were subjected to a full external and internal examination and any macroscopic abnormalities were recorded
- Organs examined: ovaries and uteri

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes (including position and type)
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: no. dead foetuses (a foetus that died shortly before necropsy)
All implantations and viable fetuses were numbered according to their intrauterine position.

Fetal examinations:

- External examinations: Yes
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No

The fetuses were killed by subcutaneous injection of sodium pentobarbitone. Fetuses from each litter were divided into two groups and examined for skeletal alterations and soft tissue alterations. Alternate fetuses were identified using an indelible marker and placed in Bouin’s fixative. Fetuses were subsequently transferred to distilled water and examined for visceral anomalies under a low power binocular microscope and then stored in 10% Buffered Formalin. The remaining fetuses were identified using cardboard tags marked with chinagraph pencil and placed 70% IMS in distilled water. The fetuses were subsequently eviscerated, processed and the skeletons stained with alizarin red S before being transferred to 50% glycerol for examination of skeletal development and anomalies and storage.

Statistics:

Female body weight change, food consumption and gravid uterus weight: Shapiro Wilk normality test and Bartlett’s test for homogeneity of variance and one way analysis of variance, followed by Dunnett’s multiple comparison test or, if unequal variances were observed, on alternative multiple comparison test. All caesarean necropsy parameters and fetal parameters: Kruskal-Wallis non-parametric analysis of variance; and a subsequent pairwise analysis of control values against treated values using the Mann-Whitney ‘U’ test, where significance was seen. Fetal evaluation parameters, including skeletal or visceral findings: Kruskal-Wallis nonparametric analysis of variance and Mann-Whitney ‘U’ test.

Indices:

Pre-and post-implantation loss, sex ratio

Historical control data:

Available at the test facility

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

At 100 mg/kg bw/d, approximately half of the females showed isolated instances of increased post-dosing salivation; this finding tended to be observed towards the end of the treatment period and on a few instances increased salivation was also observed immediately prior to dosing. Increased salivation is frequently observed when dosing via the oral gavage route and at the level observed in this study was considered to reflect distaste or slight irritancy of the test item formulations rather than any systemic effect of the test item. Neither the type nor incidence of other clinical signs observed during the study indicated any obvious effect of treatment at 10, 30 or 100 mg/kg bw/d.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

At 100 mg/kg bw/d, a mean body weight loss was apparent on the first day of treatment (Day 3 of gestation) with differences from control attaining statistical significance. Although recovery of mean body weight gain was apparent the following day, body weight gain was statistically significant lower than control until Day 8 of gestation. Thereafter, mean body weight gain was similar to control until Day 14 of gestation when statistically significant lower body weight gain was again observed to Day 17 of gestation. Subsequent mean body weight gain to termination on Day 20 of gestation was similar to control. The initial body weight loss and lower body weight gain observed at the start of the study resulted in cumulative body weight gain from the start of treatment being statistically significantly lower than control throughout gestation. Overall body weight gain on Day 20 of gestation was also statistically significantly lower than control when adjusted for the contribution of the gravid uterus. At 10 and 30 mg/kg bw/d, lower mean body weight gains were apparent for the first day of treatment (Day 3 of gestation), with differences attaining statistical significance. Thereafter there were no statistically significant differences in body weight gains from control to termination and overall body weight gain, including when adjusted for the contribution of the gravid uterus, was similar to control.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

At 100 mg/kg bw/d, food consumption was lower than control between Day 3 to Day 8 of gestation, with differences from control attaining statistical significance. Food consumption also tended to be lower than control between Days 8 and 17 of gestation, although differences did not attain statistical significance. At 30 mg/kg bw/day, food consumption was lower than control between Days 3 to 5 of gestation, with differences from control attaining statistical significance. Subsequent food consumption was similar to control throughout the remaining gestation period. At 10 mg/kg bw/day, there was no obvious effect of treatment on food consumption during gestation.

Food efficiency:

not examined

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

no effects observed

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

Other effects:

no effects observed

Details on results:

See above

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

not examined

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

not examined

Description (incidence and severity):

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

Changes in number of pregnant:

not examined

Other effects:

no effects observed

Details on maternal toxic effects:

The number of implantations, subsequent embryofetal survival, live litter size and sex ratio on Day 20 of gestation were considered to be unaffected by maternal treatment at 10, 30 or 100 mg/kg bw/day.

Key result

Dose descriptor:

NOAEL

Effect level:

30 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

Key result

Abnormalities:

no effects observed

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): not examined

Reduction in number of live offspring:

not examined

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

not examined

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

At all dosages, a lower mean incidence of incomplete ossification of the humerus attained statistical significance when compared to control, but there was no dosage relationship and, in isolation, this finding was considered to be incidental and unrelated to maternal treatment. Lower mean incidences of incomplete ossification of the frontal bones and unossified sternebra attained statistical significance when compared to control at 10 or 30 mg/kg bw/d. Additionally, the mean incidence of incomplete ossification of the frontal bones was also statistically significantly lower than control at 30 mg/kg bw/d. Collectively these findings did not indicate any obvious disturbance of fetal development and, in the absence of any similar statistically significant differences for fetuses at 100 mg/kg /bw/d, were considered to be incidental and unrelated to maternal treatment.

Visceral malformations:

no effects observed

Other effects:

no effects observed

Details on embryotoxic / teratogenic effects:

Neither the type, incidence nor distribution of findings apparent during detailed examination of fetuses on Day 20 of gestation indicated any obvious effect of maternal treatment on fetal development at 10, 30 or 100 mg/kg bw/d.

Key result

Dose descriptor:

NOEL

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No toxicologically significant effects seen at the highest dose level

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

no

Summary of female performance

Category	Number of females at dose level (mg/kg bw/d)
	0 (control)	10	30	100
Initial group size	24	24	24	24
Non-pregnant	5	2	3	1
With live young at Day 20 of gestation	19	22	21	23

 

Group Mean Litter Data Values

			Dose level (mg/kg bw/d)
			0 (control)	10	30	100
No. corpora lutea		mean sd n	14.0 3.5 19	14.6 1.8 22	13.2 4.2 21	14.4 2.5 23
No. implants		mean sd n	13.6 3.6 19	14.2 1.8 22	12.9 4.1 21	14.0 2.5 23
No. embryonic/foetal deaths	Early	mean sd n	0.1 0.2 19	0.0 0.2 22	0.1 0.3 21	0.0 0.2 23
	Late	mean sd n	0.2 0.7 19	0.2 0.5 22	0.0 0.2 21	0.1 0.3 23
	Total	mean sd n	0.2 0.7 19	0.2 0.5 22	0.1 0.4 21	0.1 0.3 23
Implantation loss %	Pre	mean sd n	2.9 5.0 19	2.5 3.4 22	1.9 3.1 21	2.8 3.7 23
	Post	mean sd n	1.9 6.9 19	1.5 3.4 22	1.2 2.6 21	0.8 2.2 23
No. live implants	Male	mean sd n	7.2 3.1 19	6.6 1.9 22	6.8 2.8 21	7.1 2.1 23
	Female	mean sd n	6.2 2.2 19	7.4 1.6 22	6.0 2.7 21	6.8 2.2 23
	Total	mean sd n	13.4 3.8 19	14.0 1.7 22	12.7 4.0 21	13. 2.5 23
% Male Foetuses		mean sd n	51.6 15.6 19	47.2 11.3 22	51.8 17.8 21	51.3 13.1 23
Mean male foetal weight (g)		mean sd n	3.66 0.310 19	3.928 0.213 22	3.999 0.227 20	3.817 0.309 23
Mean female foetal weight (g)		mean sd n	3.721 0.225 19	3.728 0.212 22	3.823 0.275 21	3.560 0.320 23
Mean foetal weight (g)		mean sd n	3.836 0.255 19	3.819 0.208 22	3.933 0.267 21	3.694 0.302 23
Mean placental weight (g)		mean sd n	0.599 0.101 19	0.622 0.091 22	0.636 0.102 21	0.599 0.068 23
Litter weight (g)		mean sd n	51.445 14.975 19	53.423 6.634 22	49.340 14.866 21	50.914 8.322 23
Total placental weight (g)		mean sd n	7.885 2.150 19	8.674 1.479 22	7.760 2.095 21	8.281 1.610 23

Conclusions:

Based on signs of toxicity at the highest dose level tested, the NOAEL for maternal toxicity was considered to be 30 mg/kg bw/d. No effects of treatment were noted for the developing foetus and the NOEL was considered to be 100 mg/kg bw/d.

Executive summary:

The potential for dimethylcyclohexylamine to cause developmental toxicity was evaluated in the rat according to OECD 414. The test item was administered by gavage to three groups each of twenty-four time mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation inclusive at dose levels 10, 30, and 100 mg/kg bw/d. A further group of twenty-four time mated females was exposed to the vehicle only (Arachis oil) to serve as a control over the same treatment period. Clinical signs, body weight change, food and water consumptions were monitored during the study. All females were terminated on Day 20 of gestation and subjected to gross necropsy including examination of the uterine contents. The number of corpora lutea, number, position and type of implantation, placental weights, fetal weight, sex and external and internal macroscopic appearance were recorded. Half of each litter were examined for detailed skeletal development and the remaining half were subjected to detailed visceral examination.

There were no mortalities during the study. Treatment at 100 mg/kg bw/d was associated with isolated instances of increased postdosing salivation in half of the females receiving this dosage. At 100 mg/kg bw/day, a mean body weight loss was apparent on the first day of treatment (Day 3 of gestation) followed by statistically significant lower bodyweight gain until Day 8 of gestation and during Days 14 to 17 of gestation compared to control. Cumulative body weight gain from the start of treatment was statistically significantly lower than control throughout gestation and overall body weight gain on Day 20 of gestation remained statistically significantly lower than control when adjusted for the contribution of the gravid uterus. At 10 and 30 mg/kg bw/d, statistically significant lower mean body weight gains were apparent for the first day of treatment (Day 3 of gestation). At 100 mg/kg bw/d, statistically significant lower food consumption was apparent between Day 3 to Day 8 of gestation and food consumption also tended to be lower than control between Days 8 and 17 of gestation. At 30 mg/kg bw/d, statistically significant lower food consumption was apparent between Day 3 to Day 5 of gestation. At 10 mg/kg bw/day, there was no obvious effect of treatment on food consumption during gestation. No abnormalities were detected at necropsy of the dams. There were no effects of treatment at any dose level on the number of implantations, subsequent embryofetal survival, live litter size and sex ratio on Day 20 of gestation. Mean foetal, placental and litter weights were unaffected by treatment. Findings at external examination of fetuses on Day 20 of gestation did not indicate any obvious effect of maternal treatment on fetal development, and there were no effects of treatment noted at detailed visceral and skeletal examination of foetuses.

Based on the results of this study, the NOAEL for the pregnant female was considered to be 30 mg/kg bw/d. A dosage of 100 mg/kg bw/d was considered to be the NOEL for the survival, growth and development of the offspring.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Guideline and GLP compliant study

Additional information

In a study conducted by van Tuyl (2010), four groups of ten Wistar Han rats/sex were exposed to cyclohexyldimethylamine (DMCHA) by dietary administration at the following dose levels: 0, 150, 500 and 1500 ppm. Males received the test substance for 28 days (2 weeks prior to mating, during mating and up to necropsy). Females were exposed for 41 -54 days (2 weeks prior to mating, during mating, during post-coitum and during at least 4 days of lactation). Clinical signs, functional observations, body weights, food consumption, reproduction parameters, observations pups, clinical pathology, macroscopy, organ weights, and histopathology were evaluated. Decreased body weights and food consumption were reported at 1500 ppm in males and females during week 1. This was considered to be due to a palatability effect of the compound. After week 1, food consumption increased to normal values and body weight gain was normal compared to the control group. Other effects on body weights were noted in females mainly during the postcoitum phase; this decrease could not be solely explained by the food consumption in these animals. One male in the 1500 ppm dose group showed slight centrilobular hepatocellular liver hypertrophy, marked, bilateral, progressive nephropathy and slight vacuolation of the zona fasciculata of the adrenal glands together with several changes for clinical biochemistry parameters, macroscopic findings and organ weight changes. As these findings were not noted in the remaining animals of this dose group, it was not deemed to be treatment related. No treatment-related changes were noted in any of the remaining parameters investigated in this study. Changes in bodyweight and food consumption at 500 ppm and 1500 ppm were not deemed to be due to DMCHA but were considered to be a palatability effect. Effects in offspring were limited to decreased body weights at 500 and 1500 ppm, which is at the same dose levels as effects on maternal body weight were noted and therefore are considered to be secondary to maternal toxicity. No other effects were observed at 500 and 1500 ppm. No treatment-related changes were noted in any of the remaining developmental parameters investigated in this study. No developmental effects were observed at 150 ppm. However, the study was not designed to look at abnormalities in foetuses. Based on the absence of treatment related effects, the No-Observed Adverse Effect Level for maternal toxicity is greater than 1500 ppm. Based on these results, the test substance does not require classification according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.

The potential for dimethylcyclohexylamine to cause developmental toxicity was evaluated in the rat according to OECD 414 (Allt, 2016). The test item was administered by gavage to three groups each of twenty-four time mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between Days 3 and 19 of gestation inclusive at dose levels 10, 30, and 100 mg/kg bw/day. A further group of twenty-four time mated females was exposed to the vehicle only (Arachis oil) to serve as a control over the same treatment period. Clinical signs, body weight change, food and water consumptions were monitored during the study. All females were terminated on Day 20 of gestation and subjected to gross necropsy including examination of the uterine contents. The number of corpora lutea, number, position and type of implantation, placental weights, fetal weight, sex and external and internal macroscopic appearance were recorded. Half of each litter were examined for detailed skeletal development and the remaining half were subjected to detailed visceral examination.

There were no mortalities during the study. Treatment at 100 mg/kg bw/day was associated with isolated instances of increased postdosing salivation in half of the females receiving this dosage. At 100 mg/kg bw/day, a mean body weight loss was apparent on the first day of treatment (Day 3 of gestation) followed by statistically significant lower bodyweight gain until Day 8 of gestation and during Days 14 to 17 of gestation compared to control. Cumulative body weight gain from the start of treatment was statistically significantly lower than control throughout gestation and overall body weight gain on Day 20 of gestation remained statistically significantly lower than control when adjusted for the contribution of the gravid uterus. At 10 and 30 mg/kg bw/day, statistically significant lower mean body weight gains were apparent for the first day of treatment (Day 3 of gestation). At 100 mg/kg bw/day, statistically significant lower food consumption was apparent between Day 3 to Day 8 of gestation and food consumption also tended to be lower than control between Days 8 and 17 of gestation. At 30 mg/kg bw/day, statistically significant lower food consumption was apparent between Day 3 to Day 5 of gestation. At 10 mg/kg bw/day, there was no obvious effect of treatment on food consumption during gestation. No abnormalities were detected at necropsy of the dams. There were no effects of treatment at any dose level on the number of implantations, subsequent embryofetal survival, live litter size and sex ratio on Day 20 of gestation. Mean foetal, placental and litter weights were unaffected by treatment. Findings at external examination of fetuses on Day 20 of gestation did not indicate any obvious effect of maternal treatment on fetal development, and there were no effects of treatment noted at detailed visceral and skeletal examination of foetuses.

Based on the results of this study, the NOAEL for the pregnant female was considered to be 30 mg/kg bw/day. A dosage of 100 mg/kg bw/day was considered to be the NOEL for the survival, growth and development of the offspring.

Justification for classification or non-classification

Effects on Fertility:

Based on the results of the study provided in the investigation of reproductive toxicity, it was not considered necessary to classify the test substance DMCHA according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.

Effects on Developmental Toxicity/Teratogenicity:

Based on the results of the study provided in the investigation of developmental toxicity / teratogenicity, it was not considered necessary to classify the test substance DMCHA according to Regulation EC No. 1272/2008 or Directive 67/548/EEC.