Methyl salicylate

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data are available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This is an old study (1963), predating GLP however the protocol and results were reported in adequate detail and included hematological studies, gross pathology, and limited histopathological examinations of key organs and tissues.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Chronic and subacute toxicology and pathology of methyl salicylate in dogs, rats, and rabbits

Author:

Webb WK, Hansen WH

Year:

1963

Bibliographic source:

Toxicol Appl Pharmacol 5: 576-687

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

MeS was blended with diet and adminstered daily for a period of 2 years.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl salicylate

EC Number:

204-317-7

EC Name:

Methyl salicylate

Cas Number:

119-36-8

Molecular formula:

C8H8O3

IUPAC Name:

methyl salicylate

Details on test material:

- Name of test material: Methyl Salicylate
- Molecular formula: C8H8O3
- Substance type: oily liquid
- Analytical purity: 99%
- Impurities (identity and concentrations):no data
- Composition of test material, percentage of components: no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data
- Other: methyl salicylate was colorless, had a specific gravity of 1.17 and had the odor of wintergreen

Test animals

Species:

rat

Strain:

Osborne-Mendel

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: no data
- Age at study initiation: weanling
- Weight at study initiation: ~ 50 g
- Fasting period before study: no data
- Housing: no data
- Diet: ad libitum
- Water: no data
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod: no data


IN-LIFE DATES: no data

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:


DIET PREPARATION
- Rate of preparation of diet (frequency): every other week
- Mixing appropriate amounts with (Type of food): no data
- Storage temperature of food: all diets were stored in sealed cans under refrigeration
- Other: 10% additional methyl salicylate was added at time of mixing to compensate for evaporation

VEHICLE: none

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

none

Duration of treatment / exposure:

2 years

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 0.1, 0.5, 1 and 2% (0, 50, 250, 500, and 1000 mg/kg bw/day)
Basis:
nominal in diet

No. of animals per sex per dose:

25/sex/dose (except for 24 males, 26 females in 2% group)

Control animals:

yes

Details on study design:

- Dose selection rationale: the data reported in the subchronic study in rats by the same authors (methyl salicylate/ dietary administration for 17 weeks in rats).

Positive control:

no data are available

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No


DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: The rats were weighed weekly.


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No


FOOD EFFICIENCY: No



OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: 3, 11, 17 and 22 months.
- Anaesthetic used for blood collection: No data
- Animals fasted: Yes
- How many animals: 10 rats/dose



CLINICAL CHEMISTRY: No


URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

none

Statistics:

not reported

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

effects observed, treatment-related

Details on results:

CLINICAL SIGNS AND MORTALITY
Animals of the 1.0% and 2.0% groups developed rough hair coats In the high-dose group, half of the animals died by week 8 and all of the animals
died by week 49 of the study.
BODY WEIGHT AND WEIGHT GAIN:
Animals of the 1.0% and 2.0% groups had statistically significant growth inhibition.
HAEMATOLOGY
no hematological effects were observed.ORGAN WEIGHTSAverage organ weights were similar for all animals. however, relative organ to body weight
ratios for the testes of male animals and for the heart and kidneys of the female animals of the 1.0% groups were significantly increased.
GROSS PATHOLOGY
gross lesions of the pituitary gland were observed in 10 animals of the 0.5% group as compared to four animals in the control
group.In the 2% group, 29 of the 50 animals had pneumonia, which appeared to be more acute than regularly observed.
HISTOPATHOLOGY: NON-NEOPLASTIC
Microscopically, the only induced lesion was a pronounced change in the bones of the rats on the 2.0% diet.
Cancellous bone in the metaphysis was increased as compared to same-age controls; this was observed to a moderate degree in five and a marked
degree in four of the nine bones examined from animals of the 2.0% group. Bone lesions were slight in 2 of 11 and 1 of 11 bones examined from
animals of the 1.0% and 0.5% groups, respectively. The affected bones had fewer osteoclasts, and the number was inversely proportional to the
degree of change.
HISTOPATHOLOGY: NEOPLASTIC
The data are limited:Malignant pituitary tumors occurred in 1 male and 2 female rats on the 0.5% diet. Mammary tumors occurred in females rats on
all diets.

Effect levels

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see below

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

The results for a supplemental study:

One male test animal died on day 11, the two others died on day 19. The females died on days 31, 40 and 71. Rough hair coat and growth inhibition was observed for all test animals, with some animals having labored respiration.

Grossly, four of the six treated rats had slight to moderate lung damage. Focal gastric hemorrhages were present in the glandular portion of three of the test animals. Bone growth was affected.

Long bones of the limbs showed reduced length and diameter compared to controls. Density of the hypophysis of long bones was increased.

Applicant's summary and conclusion

Conclusions:

Under the test conditions, growth retardation and bone lesions were reported at 1.0 and 2.0% and gross pituitary lesions at 0.5% MeS in the diet. Based on this study, the NOAEL /oral/rat is 50 mg/kg body weight/day.

Executive summary:

Webb and Hansen (1963) administered methyl salicylate in the diet to groups of male and female Osborne-Mendel rats at concentrations of 0, 0.1%, 0.5%, 1.0% or 2.0% in the diet providing doses of approximately 0, 50, 250, 500, and 1000 mg/kg bw/day for two years. All rats in the 1000 mg/kg group died by the 49th week. Body weight of both sexes was significantly decreased in the 500 and 1000 mg/kg body weight/day groups.

An increased amount of cancellous bone was present in the metaphyses in rats treated at either 500 or 1000 mg/kg body weight/day, with a more marked effect at the highest dose level. The relative testis weight of males was significantly increased as were the relative weights of the heart and kidneys of females in the 500 mg/kg body weight/day group. Gross pituitary gland lesions were increased at 250 but not 500 mg/kg bw/day compared to controls.

Based on this study, the NOAEL value is 50 mg/kg body weight/day.