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Key value for chemical safety assessment

Effects on fertility

Description of key information

Short description of key information:
Reproductive toxicity was examined in a two-generation toxicity study according to TSCA Health Effects Test Guideline for specific organ/tissue toxicity - Reproduction/Fertility effects (Union Carbide (for CMA) 1989). Sprague-Dawley rats were given daily 0, 30, 175, or 450 mg/kg bw/day p-cresol in corn oil by gavage. No effects on fertility were detected despite overt general toxicity. Thus, the NOAEL(fertility) was 450 mg/kg bw/day and the NOAEL(general toxicity) was 30 mg/kg bw/day.


 


Additional, a mixture of Meta-/Para-cresol (MPCRE; 58.7%/41.3%, respectively) was evaluated for reproductive toxicity in CD-1 (Swiss) mice using the Reproductive Assessment by Continuous Breeding (RACB) Protocol. Exposure to MPCRE, at levels ranging from a mean of 362 mg/kg/day in the low-dose group (0.25% in feed) to a mean of 1682 mg/kg/day in the high-dose group (1.5% in feed), for 14 weeks of cohabitation, did not significantly affect most measures of reproductive competence, including initial fertility, the proportion of pups born alive, or the sex of pups born alive. However, adjusted the pup weight and the number of live pups per litter (both sexes) were decreased by 5 and 20%, respectively, and cumulative days to the fifth litter were increased by almost three days in the high-dose group compared to controls. In summary, minimal reproductive toxicity was apparent, but only in the presence of significant systemic toxicity (NTP Report # RACB9000).

Link to relevant study records
Reference
Endpoint:
two-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
other: TSCA Health Effects Test Guideline for Specific Organ/Tissue Toxicity - Reproduction/Fertility Effects (EPA 1983)
Deviations:
no
Principles of method if other than guideline:
Reproductive toxicity of p-cresol was examined in a two-generation toxicity study for specific organ/tissue toxicity - Reproduction/Fertility effects.
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Kingston NY
- Age at study initiation: 6 weeks (P)
- Weight at study initiation: (P) Males: 189-191 g; Females: 141-142 g;

- Housing:
initially 2 /same sex during acclimatisationperiod; and then singly except for the cohabitation and lactation periods
- Diet ad libitum
- Water ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 68-74
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Dosing formulations were prepared by weighing the amount of test chemical into a volumetric flask and diluting to volume with certified corn oil. The resulting solutions were mixed by repeated inversions and stored at room temperature.
Details on mating procedure:
- M/F ratio per cage: 1/1
-Length of cohabitation: 21 days
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- After 7 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged singly
- Any other deviations from standard protocol: no
- M/F ratio per cage:
- Length of cohabitation:
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: [no / yes (explain)]
- After successful mating each pregnant female was caged (how):
- Any other deviations from standard protocol:
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
A standard stock solution was prepared (1 mg/ml propanol), which was used to prepare standards ranging form 10 to 100 ng/μl. With these solutions standard curve was generated using HPLC. Dosing formulation concentrations were verified by preparing aliquots which were injected on HPLC column. The measured concentration of each dosing solution was then calculated from the equitation for the standard curve developed by linear regression.
Duration of treatment / exposure:
Exposure period: 27 weeks
Premating exposure period (males): 10 weeks
Premating exposure period (females): 10 weeks
Duration of test: 29 weeks
Frequency of treatment:
P- and F1-generation: once per day, 5 days per week
F1 generation producing F2: once per daym 7 days per week
Details on study schedule:
Number of generation studies: 2
At day 28-40 post partum F1 animals were selected to be parents of the F2-generation and were gavaged with their respective formulations for at least 11 weeks on 5 days per week
The F1 animals were approximately 15-17 weeks of age at the initiation of the mating period.
they were dosed from that time point 7 days/week. Mating procedure was performed as done with the P-generation.
Remarks:
Doses / Concentrations:
0, 30, 175, 450 mg/kg bw
Basis:

No. of animals per sex per dose:
25 rats/sex/dose
Control animals:
yes, concurrent vehicle
Details on study design:
no further data
Positive control:
no data
Parental animals: Observations and examinations:
Mortality:
twice daily
General condition:
daily throughout the course of the study including skin and fur, eyes and mucous membranes, respiratory symptoms, circulatory system, autonomic and central nervous system, somatomotor activity, behavior pattern
Body weight dertermination
male, female: initially and then weekly until mating
female during gestation: day 0, 7, 13, 20 post partum day 0, 4, 7, 14, 21
Food concumption:
measured weekly during pre-breed dosing period for P and F 1 generation;
all other phases of this study determination was made visually
Oestrous cyclicity (parental animals):
vaginal smears were examined to determine pregnancy
Sperm parameters (parental animals):
no data
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 / F2 / F3] offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities,

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death wwas not determined for pups born or found dead.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals after the completion of the mating period
- Maternal animals: All surviving animals after the F1 and F2 litters have been weanded

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY
Male and female adult rats of the highest doses groups and the controls
The tissues as indicated below were prepared for microscopic examination and weighted, respectively:
Pituitary, vagina, uterus, ovaries, testes, epididmides, seminal vesicles, prostate, and other tissues with gross lesions identified as being potentially treatment-related
A complete histopathological examination was conducted for any parental animal dying on test.
Postmortem examinations (offspring):
All pups dying during lactation are necropsied to investigate the cause of death.
At weaning, postnatal day 21, 1 female and 1 male from each F1 litter is selected on a random basis to become parents of the next generation.
The remaining offspring is examined for gross external abnormalities, euthanized and discarded
Statistics:
Levene's test, ANOVA, t-test corredted by bonferroni method, Kruskal-Wallis test, Mann-Whitney U-test, Fisher's exact test
Reproductive indices:
calculated for p- and F1 animals:
Mating index (%):
---for males: number of males impregnation females divided through the total number of males paired multiplied by 100
---for females: number of females with copulation plugs divided through the number of females cohabited multiplied by 100
Fertility index(%):
---for males: number of males producing pregnant females divided through number of males impregnating females multiplied by 100
---for females: number of females with copulation plugs divided through the number of females
cohabited multiplied by 100
Gestational Index (%):
number of females with live litters divided through number of females pregnant multiplied by 100


Offspring viability indices:
calculated for F1 and F2 animals:
live birth index (%):
number of pups at birth devided through the total number of pups born multiplied by 100
4-day survival index (%):
number of pups surviving 4 days devided through the total number of live pups at birth multiplied by 100
7-day survival index(%):
number of pups surviving 7 days devided through the total number of live pups at birth multiplied by 100
14-day survival index(%):
number of pups surviving 14 days devided through the total number of live pups at birth multiplied by 100
21-day survival index(%):
number of pups surviving 21 days devided through the total number of live pups at birth multiplied by 100

Lactation omdex (%):
number of pups surviving 21 days through total number of live pups at 4 days multiplied by 100
Clinical signs:
effects observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
not specified
Histopathological findings: non-neoplastic:
not examined
Other effects:
no effects observed
Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
see section " Remarks on results"
Dose descriptor:
other: NOAEL (general toxicity)
Effect level:
ca. 30 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: >= 175 mg/kg bw/d: clinical signs of toxicity including hypoactivity, ataxia, twitches, tremors, prostration, urine stains, audible respiration, and perioral wetness 450 mg/kg bw/d: increased mortality, and reduced body weight gain
Remarks on result:
other: Generation: P and F1
Dose descriptor:
other: NOAEL (offspring)
Effect level:
ca. 175 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: based on toxic effects in the F2 litters of the high dose group animals and no clear evidence of toxic effects in F1 pups.
Remarks on result:
other: Generation: F1 and F2
Dose descriptor:
other: NOAEL (fertility)
Effect level:
ca. 450 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: No reproductive parameters were affected in either of the two generations.
Remarks on result:
other: Generation: P and F1
Clinical signs:
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
no effects observed
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings:
not specified
see section: "Remarks on results"
Dose descriptor:
NOAEL
Remarks:
fertility
Generation:
other: F1 and F2
Effect level:
450 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No reproductive parameters were affected in either of the two generations.
Dose descriptor:
NOAEL
Generation:
other: offspring
Effect level:
175 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: based on toxic effects in the F2 litters of the high dose group animals and no clear evidence of toxic effects in F1 pups.
Remarks on result:
other: Generation: F1 and F2
Dose descriptor:
NOAEL
Remarks:
fertility
Generation:
other: F1 and F2
Effect level:
450 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No reproductive parameters were affected in either of the two generations.
Dose descriptor:
NOAEL
Generation:
other: offspring
Effect level:
175 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: based on toxic effects in the F2 litters of the high dose group animals and no clear evidence of toxic effects in F1 pups.
Remarks on result:
other: Generation: F1 and F2
Reproductive effects observed:
not specified

Mortality: 8/28 males and 5/25 females at 450 mg/kg bw; 1/25 females at 30 mg/kg bw
Clinical signs of toxicity occurred in F0 and F1 males and females at 450 mg/kg bw/day and included hypoactivity, ataxia, twitches, tremors, prostration, urine stains, audible respiration, perinasal encrustation (not in F0 males), and perioral wetness occurred at >= 175 mg/kg bw.
body weight:
F0 adult males, sign reduced (p<0.01) week1 to week 13 in the 450 mg/kg bw group;
F0 adult females:
sign. reduced week 1 (p<0.05) in the 450 mg/kg bw-group,
gestational weight gain not significantly different from control group, lactational body weight sign. reduced (p<0.05) at d4 at 450 mg/kg bw group


F1 or F2: No reproductive parameters were affected in either of the two generations (mating index of male and females, fertility index of males and females, gestational index.


Still births in the F1 and F2 generations:
in F1 pups increased at 175 mg/kg/day (7/13 of one dam), but not at 450 mg/kg bw/day (low, mid, high dose versus control: 4/290 born pups, 13/312 born pups with 7/13 on one dam, 6/193 born pups) in F2 pups increased at 30 and 450 mg/kg bw, but not at 175 mg/kg/bw (low, mid, high dose versus control: 7/307 born pups, 4/265 born pups,9/163 born pups versus 0/318 born pups).


There was some variability in the number of stillborn in control groups in F1 and F2 generation (2 versus 0). There was no clear dose-dependent effect in both generations (control/low/mid/high dose: F1 pups: 2/4/13/6; F2 pups: 0/7/4/9).


F1,F2: Pup survival indices in both generations were not
affected by treatment (4-day survival index, 7-day survival index, 14-day survival index 21-day survival index and lactation index), except live birth indices in F2 (but not F1) which were reduced at 30 and 450 mg/kg bw, but not at 175 mg/kg/day. Without any other effects especially in the 30 mg/kg bw-group it is unclear whether the effects on live birth indices were substance related gross lesions of parental males and females which died prior to scheduled sacrifice included diffuse, focal or multifocal color changes in the lung and stained skin for males and lung congestion and congestion in the nasal turbinates and erythrocytes on the skin surface for females.
There were no treatment related histologic lesions observed in the examination of organs from parental F0 and F1 adults which survived to scheduled sacrifice.

Executive summary:

Reproductive toxicity was examined in a two-generation toxicity study according to TSCA Health Effects Test Guideline for specific organ/tissue toxicity - Reproduction/Fertility effects. Sprague-Dawley rats were given daily 0, 30, 175, or 450 mg/kg bw/day p-cresol in corn oil by gavage. No effects on fertility were detected despite overt general toxicity including increased mortality and reduced body weight gain at 450 mg/kg bw and at >= 175 mg/kg bw/day hypoactivity ataxia, twitches, tremors, prostration, urine stains, audible respiration and perioral wetness. Thus, the NOAEL(fertility) was 450 mg/kg bw/day and the NOAEL(general toxicity) was 30 mg/kg bw/day. The NOAEL(offspring) is 175 mg/kg bw/day due to toxic effects in the F2 litters of the high dose group animals and no clear evidence of toxic effects in F1 pups.

Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
450 mg/kg bw/day
Species:
rat
Quality of whole database:
The materials/methods and results are described in detail und are sufficient for evaluation.
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

Reproductive toxicity was examined in a two-generation toxicity study according to TSCA Health Effects Test Guideline for specific organ/tissue toxicity - Reproduction/Fertility effects (Union Carbide (for CMA) 1989).


Sprague-Dawley rats were given daily 0, 30, 175, or 450 mg/kg bw/day p-cresol in corn oil by gavage. No effects on fertility were detected despite overt general toxicity including increased mortality and reduced body weight gain at 450 mg/kg bw and at >= 175 mg/kg bw/day hypoactivity, ataxia, twitches, tremors, prostration, urine stains, audible respiration and perioral wetness. Thus, the NOAEL(fertility) was 450 mg/kg bw/day and the NOAEL(general toxicity) was 30 mg/kg bw/day. The NOAEL(offspring) is 175 mg/kg bw/day due to toxic effects in the F2 litters of the high dose group animals and no clear evidence of toxic effects in F1 pups.



Short description of key information:
Reproductive toxicity was examined in a two-generation toxicity study according to TSCA Health Effects Test Guideline for specific organ/tissue toxicity - Reproduction/Fertility effects (Union Carbide (for CMA) 1989). Sprague-Dawley rats were given daily 0, 30, 175, or 450 mg/kg bw/day p-cresol in corn oil by gavage. No effects on fertility were detected despite overt general toxicity. Thus, the NOAEL(fertility) was 450 mg/kg bw/day and the NOAEL(general toxicity) was 30 mg/kg bw/day.

Justification for selection of Effect on fertility via oral route:
key study is used

Effects on developmental toxicity

Description of key information

Developmental toxicity study according to TSCA Health Effects Test guidelines for Specific Organ/Tissue Toxicity - Developmental Toxicity. 0.0, 30.0, 175.0, or 450.0 mg/kg bw/d p-Cresol was administered by gavage to time-pregnant Sprague-Dawley rats during organogenesis and resulted in maternal toxicity and slight developmental toxicity at 450 mg/kg bw/d. Thus, the NOAEL for maternal toxicity and developmental toxicity is 175 mg/kg bw/d (CMA 1988).

Link to relevant study records
Reference
Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study
Qualifier:
according to guideline
Guideline:
other: TSCA Health Effects Test guidelines for Specific Organ/Tissue Toxicity - Developmental Toxicity (EPA, 1984,1987)
Principles of method if other than guideline:
The potential of p-cresol to produce maternal and developmental toxicity (including teratogenicity) when administered by gavage during organogenesis was evaluated in Sprague-Dawley CD rats.
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
Sprague-Dawley
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Kingston, NY
- Age at study initiation: 56 days at arrival
- Weight at study initiation: 226-230 at gd 0
- Housing: after mating singly
- Diet : ad libitum
- Water : ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 72
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Dosing formulations were prepared by weighing the amount of test chemical into volumetric flask and diluting to volume with certified corn oil. The resulting solutions were mixed by repeated inversions and stored at room temperature.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
A standard stock solution (1 mg/ml) was prepared as needed by weighing 50 mg p-cresol into a
50 ml flask and diluting to volume with propanol. Standards ranging from 10 to 100 ng/ml were
prepared by diluting the stocj solution with propanol. 10 μl of each standard was injected onto the
HPLC. the actual concentration of each dosing solution was calculated from the equitationfor the standard curve developed by linear regression.
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- Any other deviations from standard protocol:
Duration of treatment / exposure:
day 6 through day 15 of gestation
Frequency of treatment:
daily
Duration of test:
gd 21 (scheduled sacrifice)
No. of animals per sex per dose:
25 females/group; 50 control females
Control animals:
yes, concurrent vehicle
Details on study design:
no further data
Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations : mortality

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: gd 0, 6, 11, 15, 21

FOOD CONSUMPTION : Yes
- Food consumption for each animal determined throughout gestation gd 0-21

WATER CONSUMPTION : No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: body weight, liver , gravid uterine weight, number of corporal lutea, number and status of implementation sites
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- External examinations: Yes all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter
Statistics:
Levene's test, ANOVA, t-test with bonferroni prohabilities, Kruskal-wallis test, Mann-Whitney U test, Fisher's exact test
Indices:
no data
Historical control data:
no data
Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
see section "Remarks on results"
Dose descriptor:
NOAEL
Effect level:
175 mg/kg bw/day
Basis for effect level:
other: maternal toxicity
Key result
Dose descriptor:
NOAEL
Effect level:
175 mg/kg bw/day
Basis for effect level:
other: developmental toxicity
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
see section "remarks on results"
Key result
Dose descriptor:
NOAEL
Effect level:
175 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: 450 mg/kg bw/d: Slight fetotoxicity seen as three skeletal variations consistent with reduced fetal body weights
Abnormalities:
not specified
Developmental effects observed:
not specified

Maternal toxicity:
mortality: 3/25 females at 450 mg/kg bw/day
No abortions or early deliveries (1 litter at 30 mg/kg bw was fully resorbed)
450 mg/kg bw:
decreased food consumption, stat. sign. reduction in periodic maternal body weight and weight gain during dosing, maternal gestational weight gain reduced when corrected for the weight of the gravid uterus and reduced maternal terminal bw, relative but not absolute liver weight was increased clin. signs of toxicity: hypoactivity, ataxia and tremors, prone position audible respiration and perioral wetness gestational parameters were unaffected by treatment except fetal body weight per litter were reduced at 450 mg/kg bw.


Fetal evaluations:
No significant changes in the incidence of any individual malformation, malformation by category (external, visceral including craniofacial or skeletal) or total malformations for any dose group.
450 mg/kg bw:
7 skeletal variations exhibited sign. different incidences relative to those in the control groups: only 3 of these findings indicate slight fetotoxicity
--incidence of cervical centrum 6 bilobed, --reduced number of ossified caudal segments, --unossified sternebrae, reduced incidence of unossified cervical centrum no. 7, poorly ossified parietal skull bone (30 mg/kg bw), reduced incidence of some (14) proximal phalanges of the hind limb unossified an increased incidence of of poorly ossified thoracic centrum number 13 (175 mg/kg bw/d)
p-Cresol caused mild fetotoxicity at the 450 mg/kg, as seen by reduced ossification in three skeletal districts. In addition, fetal body weight was reduced at the 450 mg/kg dose level. There was no treatment-related increased incidence of malformations at any dosage.

Executive summary:

Developmental toxicity study according to TSCA Health Effects Test guidelines for Specific Organ/Tissue Toxicity - Developmental Toxicity (EPA, 1984,1987):
Administration of p-cresol by gavage to time-pregnant Sprague-Dawley rats during organogenesis at 0.0, 30.0, 175.0, or 450.0 mg/kg bw/d resulted in maternal toxicity at 450 mg/kg bw/d and included mortality, clinical signs of toxicity, reduced weight gain and food consumption during dosing and reduced gestational weight gain corrected for the gravid uterus . Slight developmental toxicity was observed at 450 mg/kg bw/d and included reduced ossification in three skeletal districts in addition with reduced fetal body weight. Thus, The NOAEL for maternal toxicity and developmental toxicity is 175 mg/kg bw/d.

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
175 mg/kg bw/day
Species:
rat
Quality of whole database:
The materials/methods and results are described in detail und are sufficient for evaluation.
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

Developmental toxicity study according to TSCA Health Effects Test guidelines for Specific Organ/Tissue Toxicity - Developmental Toxicity : Administration of p-cresol by gavage to time-pregnant Sprague-Dawley rats during organogenesis at 0.0, 30.0, 175.0, or 450.0 mg/kg bw/d resulted in maternal toxicity at 450 mg/kg bw/d and included mortality, clinical signs of toxicity, reduced weight gain and food consumption during dosing and reduced gestational weight gain corrected for the gravid uterus . Slight developmental toxicity was observed at 450 mg/kg bw/d and included reduced ossification in three skeletal districts in addition with reduced fetal body weight. Thus, the NOAEL for maternal toxicity and developmental toxicity is 175 mg/kg bw/d (CMA 1988).


 


In addition, in another developmental toxicity study according to TSCA Health Effects Test guidelines for Specific Organ/Tissue Toxicity -Developmental Toxicity (EPA, 1984, 1987) p-cresol was administered by gavage to time-pregnant New Zealand White rabbits during organogenesis at 0.0, 5.0, 50.0 or 100 mg/kg bw/day resulting in maternal toxicity at 50.0 and 100.0 mg/kg bw/d including mortality and clinical signs of toxicity. No indications of developmental toxicity were observed. Thus, the NOAEL (maternal toxicity) is 5 mg/kg bw/d and the NOAEL for developmental toxicity is 100 mg/kg bw/d (CMA 1988)


.

Justification for selection of Effect on developmental toxicity: via oral route:
The most reliable study is used as key study

Toxicity to reproduction: other studies

Additional information

no study available

Justification for classification or non-classification

Based on the results of the 2-generation study and the developmental toxicity studies a classification is not required.

Additional information