Benzoic acid, 4-hydroxy-, C18-22-alkyl esters

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study, conducted similar to guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1974

Report date:

1974

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)

Version / remarks:

(1984)

Deviations:

no

Principles of method if other than guideline:

The study was conducted before appropriate test guidelines and GLP were introduced.

GLP compliance:

no

Type of assay:

rodent dominant lethal assay

Test material

Test material information

Constituent 1

Reference substance name:

Methyl 4-hydroxybenzoate

EC Number:

202-785-7

EC Name:

Methyl 4-hydroxybenzoate

Cas Number:

99-76-3

IUPAC Name:

methyl 4-hydroxybenzoate

Details on test material:

- Name of test material (as cited in study report): Methylparaben
- Analytical purity: no adta
- Lot/batch No.: 1674K
- Other: used as supplied by the Food and Drug Administration

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: a closed colony (random-bred, not further specified)
- Age at study initiation: 10-12 weeks
- Weight at study initiation: 280 - 350 g (400 g in case of high dose group rats)
- Housing: in groups of 5. Sanitary cages and bedding were used and changed 2 times per week, at which time water containers were cleaned, sanitised and filled. Once a week, cages were repositioned on racks; racks were repositioned within rooms monthly.
- Diet: commercial 4% fat diet, ad libitum until animals were introduced into the experiment
- Water: ad libitum
- Acclimation period: 4-11 days

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: physiol. saline (0.85%)

Duration of treatment / exposure:

not applicable

Frequency of treatment:

- single exposure: single oral administration
- repeated exposure: once daily on 5 consecutive days, 24 h apart

Post exposure period:

8 weeks (sequential matings)

Doses / concentrations

Remarks:

Doses / Concentrations:
5, 50, 500, 5000 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

10 males

Control animals:

yes, concurrent vehicle

Positive control(s):

Triethylene Melamine, 0.3 mg/kg bw, intraperitoneal injection

Examinations

Tissues and cell types examined:

- Determination of fertility index
- Necropsy of the uteri of mated females, analysing early deaths (deciduomata), absorptions, dead implatations, total implantations and number of Corpora lutea

Details of tissue and slide preparation:

Following treatment, the males were sequentially mated to 2 females per week for 8 weeks (7 weeks in the subacute study). Females were killed 14 days after separating from the males, and at necropsy the uterus was examined for deciduodimata, late foetal deaths and total implantations. Corpora lutea, early fetal deaths, late fetal deaths and total implantations per uterine horn were recorded.

Evaluation criteria:

Each male was mated with 2 females per week, and this provided for an adequate number of implantations per group per week (200 minimum) for negative controls, even if there was a 4-fold reduction in fertility of implantations.

Statistics:

yes, please refer to "any other information on materials and methods incl. tables".

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

yes

Remarks:

at 1000 mg/kg bw and above

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
Test 1:
- 1000 mg/kg: 1/5 animals dead (Day 3)
- 2000 mg/kg: 2/5 animals dead (Day 2)
- 3000 mg/kg: 4/5 animals dead (Day 1: 3 animals, Day 2: 1 animal)
- 4000 mg/kg: 4/5 animals dead (Day 1: 4 animals)
- 5000 mg/kg: 10/10 animals dead (Day 1: 10 animals)
All animals showed reddened stomach lining and lungs congested. The LD50 value was determined to be 2100 mg/kg bw using the Litchfield-Wilcoxon method.

Test 2:
A single dose of 5000 mg/kg bw was administered to 10 male rats (average body weight: 262 g). No signs of toxicity or abnormal behavior were observed in the 7-day observation period. No deaths occured. At termination all animals were killed and on necropsy no gross findings were observed. The LD50 value was determined to be >5000 mg/kg bw.

RESULTS OF DEFINITIVE STUDY
- 5, 50, 500 mg/kg bw (single exposure):
Significant decreases in average Corpora lutea and preimplantation losses were seen in the experimental groups of Weeks 1, 4 and 5.

- 5, 50, 500 mg/kg bw/day (repeated exposure):
Significant increases in average implantations and Corpora lutea were seen in the experimental groups at week 4. Significant, dose-related increases were seen in average resorptions at 500 mg/kg bw/day at Weeks 1 and 6.

- 5000 mg/kg bw/d (single and repeated exposure):
Treated animals did not significantly vary from those of the vehicle control group, except for a significant increase in the number of dead implants per total of weeks 2 and 6. In these respective examples 1 and 2 were found with 6 or more dead embryos. Omission of these animals from the sample would bring the calculated values into line with those determined for the vehicle controls. Whether these are sporadic phenomena or due to compound effects cannot be determined from the data, although the former is suggested by the lack of effect on the other parameters. The positive control substance Triethylene Melamine caused significant preimplatation loss and embryo resorptions during the first 5 weeks.
Comparing the values obtained by application with 5000 mg/kg bw/day with those of the animals treated with 5, 50, and 500 mg/kg bw/day revealed no dose response or time trend patterns, which would suggest a dominant lethal effect for the test item.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative