4-hydroxybenzoic acid

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented study which meets basic scientific principles

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 422 Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test

Deviations:

yes

Remarks:

: duration, number of animals, dosages, administration volume, hematology, clinical chemistry, organ weights, histopathologic examination, neurobehaviour

Principles of method if other than guideline:

daily administration by stomach tube : males for 42 days, females for 38 -52 days
13 animals per each sex and dose group were treated (whereas OECD 422 recommends that each group is started with at least 10 animals of each sex)

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-hydroxybenzoic acid

EC Number:

202-804-9

EC Name:

4-hydroxybenzoic acid

Cas Number:

99-96-7

Molecular formula:

C7H6O3

IUPAC Name:

4-hydroxybenzoic acid

Details on test material:

- Name of test material: 4-hydroxybenzoic acid
- Physical state: solid, white crystalline powder
- Analytical purity: 99.7%
- Impurities (identity and concentrations): 0.02 (w/w)% salicylic acid, 0.03 (w/w)% 4-hydroxyisophthalic acid
- Lot/batch No.: GI0681
- supplier: Ueno Seikyku Co., LTD.
- Storage condition of test material: room temperature

Test animals

Species:

rat

Strain:

other: Sprague-Dawley, Crj:CD, SPF

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Nippon Charles River Co., Ltd., Hino Rearing Center
- Age at purchase: 7 weeks
- weight rage at time of grouping: males 305.3 - 348.0 g, females 206.6 - 233.9 g
- Fasting period before study: no
- Housing: individually in metal cages with mesh floor (22 x 27 x 19 cm³) in a rearing room
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: one week
- Sex: male, female


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 +/- 1
- Humidity (%): 50-65
- Air changes (per hr): 15 times
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

VEHICLE: suspension in water
- Concentration in vehicle: 0.5% Carboxymethyl Cellulose Sodium (CMC), Maruishi Seiyaku Co. Ltd., Production No. 1527),
Japan Pharmacopeia injection-quality water, Hikari Seiyaku Co. Ltd., Production No. 9510AH
- Amount of vehicle: 5 ml/kg

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1 (Probably) (male animals: see Repeated dose Toxicity)
- Length of cohabitation: until copulation/ up to 14 days
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

males: 42 administrations, (2 weeks before mating, 2 weeks during mating and 2 weeks after mating period)
females: in total up to 52 days: 14 days pre-mating period and up to 14 days mating period (until copulation), through the pregnancy period (assuming 20 days pregnancy) until lactation day 3 after delivery (4 days lactation period)

Frequency of treatment:

daily by stomach tube

Duration of test:

up to 52 days

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 40, 200, 1000 mg/kg bw./day
Basis:
actual ingested
Doses are based on the weekly measured body weights/body weights at the beginning of the pregnancy.

No. of animals per sex per dose:

13

Control animals:

yes

Details on study design:

- Control groups: aqueous solution of 0.5% CMC Na
- Dose selection rationale:
Results of a pilot study with 14-days repeated oral administration to male and female rats:
250 mg/kg bw : salivation, abnormal respiratory sounds, rhinorrhea
females: reduced body weight gain
1000 mg/kg bw: salivation, abnormal respiratory sounds, rhinorrhea, reduced body weight gain,
females: reduced: food consumption
- Rationale for animal assignment: ramdomly grouped
- Section schedule rationale: all animals werde sacrificed

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: on administration days 1, 8, 15, 22, 29, 36, 42 and on day of autopsy

FOOD CONSUMPTION : on administration days 1, 8, 29, 36, 42
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No

WATER CONSUMPTION): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on lactation day 4 (starting with day 0)
- Organs examined: liver, kidneys, lung, thymus, heart, urinary bladder, spleen

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of corpora lutea: Yes
- Number of implantations: Yes

Fetal examinations:

- External examinations: Yes: [all per litter]

Statistics:

Mean graded data for histopathological findings were tested for significant differences between the control and various dosage groups using Mann-Whitney's U-test, and positive grade totals using Fisher's direct probability one-tailed test. For all other data, which values obtained for individuals the uniformity of distribution of the various groups was first tested by Bartlett's method. When this resulted in a uniform distribution, a one-dimensional distribution analysis was performed, and when intergroup significance was observed, the differences in the mean values between the control and various dosage groups were tested using Dunnett's method if the number of animals per group was the same, or Scheffé's method when it was not. When the distribution was not uniform or when there were groups for which the distribution was 0, the Kruskal-Wallis rank sum test was performed. When intergroup significance was observed, Dunnett's or Scheffé's method tests the differences between the control and various dosage groups were performed. The level of significance was 5% or 1%.

Indices:

implantation/fertility index, delivery index, live birth index, neonatal survival rate, copulation index, pairing days until copulation, lactation status, gestation period

Historical control data:

no

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

With doses 200 mg/kg bw. and above abnormal respiratory sounds or transient post-administration salivation

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

suppressed weight gain in males with doses of 1000 mg/kg bw./day

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

With doses 200 mg/kg bw. and above reduced lymophocyte ratio was abserved

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

In males with doses of 200 mg/kg bw and above reduced glucose was observed.
With dose of 1000 mg/kg bw. reduced total protein and elevated GPT, GOT and increased A/G ratio was observed.

Endocrine findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Maternal developmental toxicity

Number of abortions:

no effects observed

Pre- and post-implantation loss:

not examined

Total litter losses by resorption:

no effects observed

Early or late resorptions:

not examined

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

Maternal toxic effects: yes.

Details on maternal toxic effects:
NOEL: 40 mg/kg bw
-200 mg/kg bw: abnormal respiratory sounds: 3 animals 1-2 times
-1000 mg/kg bw: salivation: 13 animals 2-23 times, rhinorhea: 1 animal 1time, abnormal respiratory sounds: 9 animals 1-10 times, lungs: inflamatory foci (1 in the control group, 4 cases in the dosage group)

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOEL

Effect level:

40 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Key result

Dose descriptor:

NOEL

Effect level:

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

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Anogenital distance of all rodent fetuses:

not examined

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

not examined

Visceral malformations:

no effects observed

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects: no effects

Effect levels (fetuses)

Key result

Dose descriptor:

NOEL

Effect level:

> 1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reduction in number of live offspring

changes in sex ratio

fetal/pup body weight changes

changes in litter size and weights

changes in postnatal survival

external malformations

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

NOEL: 40 mg/kg bw.
200 mg/kg bw: clinical signs: abnormal respiratory sounds: 3 animals 1-2 times
1000 mg/kg bw: salivation: 13 animals 2-23 times, rhinorhea: 1 animal 1time, abnormal respiratory sounds: 9 animals 1-10 times,
histopathology: lung: inflammatory foci (1 in the control group, 4 cases in the dosage group)
No differences: food consumption, body weight, histopathology, organ weights, copulation index, number of pregnant animals, number of pregnant animals with pups alive, fertility index, pairing days until copulation, frequeny of vaginal estrus, delivery status, lactation status, birth rate, gestation index, birth index, live birth index, gestation period, number of corpora lutea, number of implantation sites, implantation index, pup weight, pup weight gain, sex ratio, viability index

Executive summary:

Daily dosages of 0, 40, 200, and 1000 mg/kg bw. were administered by stomach tube to groups of 13 male and female rats for a 14 days pre-mating period, for a mating period up to 14 days. Whereas OECD 422 recommends that each group is started with at least 10 animals of each sex. The administration to the males was continued for 2 further weeks, totally 42 days. The administration to the females was continued for the pregnancy period of 20 days and for a lactation period of 4 days. All in all between 38 to 52 days (depending on the mating period).

The test-article was formulated in 0.5%CMC , the administration volume was 5 ml/kg bw.

NOEL: 40 mg/kg bw..

200 mg/kg bw.: abnormal respiratory sounds: 3 animals 1-2 times,

1000 mg/kg bw: salivation: 13 animals 2-23 times, rhinorhea: 1 animal 1time, abnormal respiratory sounds: 9 animals 1-10 times, histopathology: lung inflammatori foci.