Formaldehyde, reaction products with m-phenylenediamine, sodium sulfide (Na2S) and sulfur

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

No parental, reproduction and developmental toxicity was observed up to the highest dose level tested (1000 mg/kg) in a subacute reproduction toxicity screening study according to OECD 422. The NOAEL was >1000 mg/kg bw.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 May 2012 - 10 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline 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

Qualifier:

according to guideline

Guideline:

other: EPA, Health Effects Test Guidelines OPPTS 870.3650, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test, July 2000.

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: The United States EPA Health Effects Test Guidelines, OPPTS 870.3550, Reproduction/Developmental Toxicity Screening Test, July 2000.

Deviations:

no

Principles of method if other than guideline:

In addition, the procedures described in the report essentially conform to the following guidelines:
- Commission regulation (EC) No 440/2008 Part B: Methods for the Determination of Toxicity and other Health Effects; B.7: "Repeated Dose (28 days) Toxicity (oral)". Official Journal of the European Union No. L142, May 2008.
- OECD Guidelines for Testing of Chemicals, Guideline 407, Repeated Dose 28-day Oral Toxicity Study in Rodents, October 2008.
- The United States EPA Health Effects Test Guidelines, OPPTS 870.3050, Repeated dose 28-day oral toxicity study in rodents, July 2000.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
Nulliparous and nonpregnant females and untreated animals were used at initiation of the study.
- Age at study initiation: Approximately 11 weeks.
- Weight at study initiation: mean weight at start of treatment was 328 gr (males) or 208 gr (females).
- Fasting period before study: no
- Housing:
Pre-mating: Animals were housed in groups of 5 animals/sex/cage in Macrolon cages.
Mating: Females were caged together with males on a one-to-one-basis in Macrolon cages.
Post-mating: Males were housed in their home cage with a maximum of 5 animals/cage. Females were individually housed in Macrolon cages. Pups were kept with the dam until termination
Lactation: Pups were kept with the dam until termination in Macrolon cages.
General: Sterilised sawdust as bedding material and paper as cage-enrichment were supplied. During locomotor activity monitoring, animals were housed individually in a Hi-temp polycarbonate cage (Ancare corp., USA; dimensions: 48.3 x 26.7 x 20.3 cm) without cage-enrichment or bedding material.
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, approximately 15 room air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.

IN-LIFE DATES
From: 18 May 2012 - 10 July 2012

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on exposure:

- Method of formulation: Formulations (w/w) were prepared daily within 4 hours prior to dosing and were homogenized to a visually acceptable level. No adjustment was made for specific gravity/density of the test substance, vehicle, and/or formulation. A correction was made for the purity of the test substance (13.5%).
- Storage conditions of formulations: At ambient temperature.
- Justification for use and choice of vehicle (if other than water): Based on trial formulations performed at WIL Research Europe and on information provided by the Sponsor.
- Dose volume: 20 mL/kg body weight. Actual dose volumes were calculated according to the latest body weight.

Details on mating procedure:

- M/F ratio per cage:1/1 (one female was cohabitated with one male of the same treatment group, avoiding sibling mating.
- Length of cohabitation: A maximum of 14 days was allowed for mating.
- Proof of pregnancy: Detection of mating was confirmed by evidence of sperm in the vaginal lavage, by staging of the estrous cycle and/or 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 14 days was allowed for mating, after which females who had not shown evidence of mating were separated from their males.
- After successful mating each pregnant female was caged individually in Macrolon cages (MIII type, height 18 cm).

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were conducted on Day 4 (21 May 2012) and at the end of treatment (02 July 2012), using gravimetry. Samples of formulations of Day 4 were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Samples at end of treatment were analyzed for accuracy of preparation only. All samples were collected and analysed in duplicate. Stability in vehicle over 4 hours at room temperature could not be determined analytically (IR spectrophotometry; see Results). The accuracy of preparation was considered acceptable if the mean measured concentrations were 85-115% of the target concentration. Homogeneity was demonstrated if the coefficient of variation was ≤ 10%.

Duration of treatment / exposure:

Males were exposed for 31 days, i.e. 2 weeks prior to mating, during mating, and up to the day prior to scheduled necropsy. Females were exposed for 46-53 days, i.e. during 2 weeks prior to mating, during mating, during post-coitum, and during at least 4 days of lactation (up to the day prior to scheduled necropsy). ( 3, 1, 2, 2 females of group 1, 2, 3, 4, respectively were not dosed during littering). Pups were not dosed directly but could have potentially be exposed to the test substance in utero, via maternal milk or from exposure to maternal urine/faeces.

Frequency of treatment:

Once daily for 7 d/w.

Details on study schedule:

- Age at mating of the animals in the study: Approximately 13 weeks

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Dose / conc.:

300 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

0 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were based on results of a 10-day dose range finding study (Project 499623: Based on the results of this range finding study, dose levels for the main study (28 days toxicity study) were 100, 300 and 1000 mg/kg body weight. No clinical signs were observed. Therefore, clinical observations in the main study were conducted immediately after dosing, and functional observation tests were conducted after dosing at no specific time point, but within a similar time period after dosing for the respective animals.)
- Selection of animals for selected measurements: 5 animals/sex/group were randomly selected at allocation for functional observations, clinical pathology, macroscopic examination (full list), organ weights (full list) and histopathology. Only females with live offspring were selected.
- Parturition: The females were allowed to litter normally. Day 1 of lactation was defined as the day when a litter was found completed (i.e. membranes, placentas cleaned up, nest built up and/or feeding of pups started). Females that were littering were left undisturbed.
- Identification of pups: On Day 1 of lactation, all pups were individually identified by means of subcutaneous injection of Indian ink.

Positive control:

Not required.

Parental animals: Observations and examinations:

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

DETAILED CLINICAL OBSERVATIONS
- Time schedule: Daily, detailed clinical observations were made in all animals, at least immediately (0-15 min) after dosing. Once prior to start of treatment and at weekly intervals during the treatment period this was also performed outside the home cage in a standard arena. The time of onset, grade and duration of any observed sign was recorded. Signs were graded for severity.

BODY WEIGHT
- Time schedule for examinations: Males and females were weighed 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
- Weekly, for males and females. Food consumption was not recorded during the mating period. 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.

FOOD EFFICIENCY
Yes

WATER CONSUMPTION
No. Subjective appraisal was maintained during the study, but no quantitative investigation introduced as no effect was suspected.

OPHTHALMOSCOPIC EXAMINATION
No

HAEMATOLOGY
- Time schedule for collection of blood: immediately prior to scheduled post mortem examination.
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes (with a maximum of 24 hours). Water was provided.
- How many animals: 5 animals/sex/group
- Parameters checked were: According to test guidelines, and including Met-haemoglobin.

CLINICAL CHEMISTRY
- Time schedule for collection of blood: immediately prior to scheduled post mortem examination.
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes (with a maximum of 24 hours). Water was provided.
- How many animals: 5 animals/sex/group
- Parameters checked were: According to test guidelines

URINALYSIS
No

NEUROBEHAVIOURAL EXAMINATION
- Time schedule for examinations: The selected males were tested during Week 4 of treatment and the selected females were tested during lactation (all before blood sampling).
- Dose groups that were examined: all
- Battery of functions tested: According to test guidelines

GENERAL REPRODUCTION DATA
- Male number paired with, mating date, confirmation of pregnancy, and delivery day was recorded.
- Pregnant females were examined to detect signs of difficult or prolonged parturition, and cage debris of these females was examined to detect signs of abortion or premature birth.
- Any deficiencies in maternal care (such as inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups or apparently inadequate lactation or feeding) were examined.

Oestrous cyclicity (parental animals):

Not determined.

Sperm parameters (parental animals):

Slides of the testes were prepared for histopathological staging of spermatogenesis (selected 5 males of the control and high dose group and animals suspected to be infertile).

Litter observations:

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

- Mortality: The numbers of live and dead pups on Day 1 of lactation and daily thereafter were determined. If possible, defects or cause of death were evaluated.
- Clinical signs: At least once daily, detailed clinical observations were made in all animals.
- Body weights: Live pups were weighed on Days 1 and 4 of lactation.
- Sex: Sex was determined for all pups on Days 1 and 4 of lactation (by assessment of the ano-genital distance).

GROSS EXAMINATION OF DEAD PUPS
Yes, if possible, defects or cause of death were evaluated.

Postmortem examinations (parental animals):

GROSS PATHOLOGY
- All animals were fasted overnight (with a maximum of 24 hours) prior to planned necropsy, but water was provided. Animals surviving to scheduled necropsy and all moribund animals were deeply anaesthetised and subsequently exsanguinated.
- The number of former implantation sites and corpora lutea were recorded for all paired females.
- Selected 5 animals/sex/group and all animals that died spontaneously or were killed in extremis: According to test guidelines
- All remaining animals and females which failed to deliver: According to test guidelines

ORGAN WEIGHTS
- Selected 5 animals/sex/group: According to test guidelines
- All remaining males: Epididymides and Testes

HISTOPATHOLOGY
- According to test guidelines

Postmortem examinations (offspring):

SACRIFICE
Pups surviving to planned termination were killed by decapitation on lactation Days 5-7.

GROSS NECROPSY
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. Any abnormal pup, organ or tissue was preserved in 10% buffered formalin for possible further examination.

HISTOPATHOLOGY / ORGAN WEIGHTS
No.

Statistics:

The following statistical methods were used to analyze the data:
- If the variables could be assumed to follow a normal distribution, the Dunnett-test (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
- The Steel-test (many-to-one rank test) was applied if the data could not be assumed to follow a normal distribution.
- The Fisher Exact-test was applied to frequency data.
- The Kruskal-Wallis nonparametric ANOVA test was applied to motor activity data to determine intergroup differences. In case intergroup differences were seen, the Wilcoxon test was applied 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. Group means were calculated for continuous data and medians were calculated for discrete data (scores) in the summary tables. 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.

Reproductive indices:

For each group, the following calculations were performed:
- Mating index: Number of females mated/Number of females paired x 100
- Fertility index: Number of pregnant females/Number of females paired x 100
- Conception index: Number of pregnant females/Number of females mated x 100
- Gestation index: Number of females bearing live pups/Number of pregnant females x 100
- Duration of gestation: Number of days between confirmation of mating and the beginning of parturition

Offspring viability indices:

- Percentage live males at First Litter Check: Number of live male pups at First Litter Check/Number of live pups at First Litter Check x 100
- Percentage live females at First Litter Check: Number of live female pups at First Litter Check/Number of live pups at First Litter Check x 100
- Percentage of postnatal loss Days 0-4 of lactation: Number of dead pups on Day 4 of lactation/Number of live pups at First Litter Check x 100
- Viability index: Number of live pups on Day 4 of lactation / Number of pups born alive x 100

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

not examined

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

MORTALITY
No mortality occurred during the study period.

CLINICAL SIGNS
No clinical signs of toxicity were noted during the observation period. Scabs and alopecia 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. At the incidence observed, these were considered signs of no toxicological relevance.

FUNCTIONAL OBSERVATIONS
Hearing ability, pupillary reflex, static righting reflex and grip strength were normal in all animals. The variation in motor activity did not indicate a relation with treatment. All groups showed a similar habituation profile with high activity in the first interval that decreased over the duration of the test period.

BODY WEIGHTS
No toxicologically relevant changes in body weights and body weight gain were noted. The statistically significant lower body weight gain of males at 1000 mg/kg (whole mating period) and 300 mg/kg (Day 8 of the mating period) was minor in nature, and did not show a clear dose-related trend. No toxicological relevance was therefore ascribed to this change.

FOOD CONSUMPTION
Food consumption before or after allowance for body weight was similar between treated and control animals.

HAEMATOLOGY
No toxicologically relevant changes occurred in haematological parameters of treated rats. The statistically significant increase in relative Met-haemoglobin content of males at 1000 mg/kg (and an apparent increase among females of this dose group) was slight in nature. Also, since other red blood cell parameters were unaffected by treatment, this change was considered to be of no toxicological relevance. The statistically significant lower white blood cell count of females at 100 mg/kg was considered to be of no toxicological relevance as this change occurred in the absence of a dose-related trend and remained within the range considered normal for rats of this age and strain.

CLINICAL BIOCHEMISTRY
No toxicologically relevant changes occurred in clinical biochemistry parameters of treated rats. The statistically significant higher chloride level of males at 100 mg/kg was considered to be of no toxicological relevance as this change occurred in the absence of a dose-related trend and remained within the range considered normal for rats of this age and strain.

MACROSCOPIC EXAMINATION
Necropsy did not reveal any toxicologically relevant alterations. The incidence macroscopic findings among control and treated animals was within the background range of findings that are encountered among rats of this age and strain, and did not show a doserelated incidence trend. These necropsy findings were therefore considered to be of no toxicological relevance, and consisted of a diaphragmatic hernia of the liver, a yellowish soft nodule on the epididymides, pelvic dilation of the kidneys, reduced size of the preputial glands, alopecia, thickened left horn of the uterus, tan or yellowish foci on the clitoral glands, tan discolouration of the clitoral glands, red foci on the glandular mucosa of the stomach and red foci on the thymus.

ORGAN WEIGHTS
No toxicologically relevant changes were noted in organ weights and organ to body weight ratios. All statistically significant changes in organ weight and organ to body weights remained within the range considered normal for rats of this age and strain, occurred in the absence of a dose-related trend, and/or had no histopathological correlates. No toxicological relevance was therefore ascribed to these changes, which consisted of a higher relative kidney and seminal vesicle weight of males at 1000 mg/kg, and higher absolute and relative ovary weight at 100 and 300 mg/kg.

MICROSCOPIC EXAMINATION
There were no microscopic findings in any of the animals suspected of infertility which could explain their lack of reproductive performance. All recorded microscopic findings were within the range of background pathology encountered in Wistar (Han) rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats. The spermatogenic staging profiles were normal for evaluated control males and males at 1000 mg/kg.

REPRODUCTIVE DATA
Mating, fertility and conception indices, precoital time, and number of corpora lutea and implantation sites were unaffected by treatment.
The statistically significant higher number of corpora lutea at 300 mg/kg occurred in the absence of a dose-related trend, and was therefore considered to be of no toxicological relevance.

DEVELOPMENTAL DATA
Gestation index and duration, parturition, maternal care and early postnatal pup development (mortality, clinical signs, body weight and macroscopy) were unaffected by treatment.

PARTURITION/MATERNAL CARE
No signs of difficult or prolonged parturition were noted among the pregnant females. Examination of cage debris of pregnant females revealed no signs of abortion or premature birth. No deficiencies in maternal care were observed.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No toxicity was observed up to the highest dose level tested.

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings:

not examined

EARLY POSTNATAL PUP DEVELOPMENT
Number of dead and living pups at first litter check, postnatal loss, viability index and sex ratio were unaffected by treatment, and clinical signs, body weight and external macroscopy did not reveal treatment-related findings.

MORTALITY PUPS
One pup at 100 mg/kg and two pups at 300 mg/kg were found dead or missing during lactation. Pups missing were most likely cannibalised. No toxicological relevance was attributed to these dead/missing pups since the mortality incidence did not show a dose-related trend and remained within the range considered normal for pups of this age. For two pups of two litter of group 1, the date of (planned) necropsy was not recorded, and hence it could not be excluded that these animals were missing.

CLINICAL SIGNS PUPS
The incidence of a wound on the left hind leg noted for one pup of a litter at 100 mg/kg remained within the range considered normal for pups of this age, and was therefore considered to be of no toxicological relevance.

BODY WEIGHT PUPS
Body weights of pups were considered to have been unaffected by treatment.

MACROSCOPY PUPS
All pups of one litter at 100 mg/kg showed no milk in the stomach at necropsy. Since this was confined to a single litter, and since these pups did show milk in the stomach up to and including the last litter check, no toxicological relevance was ascribed to this finding.

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No toxicity was observed up to the highest dose level tested.

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

The mean concentrations analysed in the formulations of Group 2, Group 3 and Group 4 prepared for use on Day 4 were 60, 87 and 88% respectively. The mean concentrations analysed in the formulations of Group 2, Group 3 and Group 4 prepared for use at the end of treatment were 84, 76 and 86% respectively. Results for Group 2, Group 3 and Group 4 were corrected for the mean of Group 1 and their sample weight. The coefficient of variation for the formulations of Group 2, Group 3 and Group 4 prepared for use on Day 4 were 26, 7.9 and 3.3% respectively. Major peaks in the IR spectra of the formulations derived from the vehicle (water and carboxymethylcellulose). The only peak that derived from the test substance was observed at 1120 cm-1. Given the minor size of this peak, no conclusion could be drawn on stability of the formulations.

Conclusions:

Based on this OECD 422 study in rats, a parental, reproduction and developmental No Observed Adverse Effect Level (NOAEL) of at least 1000 mg/kg/day was derived (based on main component C.I. Leuco Sulphur Brown 37, corresponding to approximately 7407 mg test substance including C.I. Leuco Sulphur Brown 37/kg body weight).

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

1 reliable without restriction

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Reproduction toxicity screening, OECD 422, oral
After acclimatization, four groups of ten male and ten female Wistar Han rats were exposed by oral gavage to the test substance at 0, 100, 300 and 1000 mg/kg/day (based on main component C.I. Leuco Sulphur Brown 37). Males were exposed for 31 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 46-53 days, i.e. during 2 weeks prior to mating, during mating, during post-coitum, and during at least 4 days of lactation.
Evaluated parameters:
The following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (Week 4 (males); end of lactation (females)), body weight and food consumption (at least at weekly intervals), clinical pathology (Week 4 (males); end of lactation (females)), macroscopy at termination, organ weights and histopathology on a selection of tissues, and reproduction/developmental parameters, consisting of mating, fertility and conception indices, precoital time, number of corpora lutea and implantation sites, gestation index and duration, parturition, maternal care, sex ratio and early postnatal pup development (mortality, clinical signs, body weights and macroscopy). Formulations were analyzed during the study to assess accuracy, homogeneity and stability.
No parental, reproduction and developmental toxicity was observed up to the highest dose level tested (1000 mg/kg).

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

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

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available study is considered reliable for this assessment.

Based on the above stated assessment of the reproduction toxicity potential of the test substance, it is deemed that the compound is not toxic to the reproduction and do not need to be classified according to CLP (Regulation (EC) No 1272/2008 of the European Parliament and of the Council), as amended for the eighteenth time in Regulation (EU) 2022/692.