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Administrative data

Description of key information

NOAEL subacute oral study with homosalate: 300 mg/kg bw/day
NOAEL (for homosalate) from subchronic oral study with read-across substance methyl salicylate: 86 mg/kg bw/day
NOAEC (for homosalate) from subacute inhalation study with read-across substance methyl salicylate: 1207 mg/m³

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
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.
Reason / purpose:
reference to same study
Qualifier:
no guideline available
Principles of method if other than guideline:
MeS was blended with diet and administered daily for a period of 2 years.
GLP compliance:
no
Limit test:
no
Species:
rat
Strain:
Osborne-Mendel
Sex:
male/female
Details on test animals 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
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:
once daily
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
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
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.
Dose descriptor:
NOAEL
Effect level:
50 mg/kg bw/day (nominal)
Sex:
male/female
Basis for effect level:
other: for methyl salicylate
Dose descriptor:
NOAEL
Effect level:
86 mg/kg bw/day (nominal)
Sex:
male/female
Basis for effect level:
other: read-across value for homosalate
Critical effects observed:
not specified

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.

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 for methyl salicylate. This corresponds to 86 mg/kg bw/day of homosalate.
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.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
86 mg/kg bw/day
Study duration:
chronic
Species:
rat
Quality of whole database:
A chronic study with the read-across substance methyl salicylate and a subacute study with homosalate gave consistent results

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Single concentration tested. No data on substance purity.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)
GLP compliance:
no
Species:
rat
Strain:
other: Alderley Park
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Alderley Park
- Age at study initiation: no data
- Weight at study initiation: mean 200g
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: no data
Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Remarks on MMAD:
MMAD / GSD: Not applicable, vapour
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
7 hours per day, 5 days per week
Remarks:
Doses / Concentrations:
700 mg/m3
Basis:
nominal conc.
No. of animals per sex per dose:
4
Details on study design:
not given
Positive control:
no data
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: Daily

FOOD CONSUMPTION: - No data

FOOD EFFICIENCY:- No data

WATER CONSUMPTION: No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: No data
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: No data

CLINICAL CHEMISTRY: No data

URINALYSIS: Yes
- Time schedule for collection of urine: Overnight after last exposure
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data

NEUROBEHAVIOURAL EXAMINATION: No data
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
Other examinations:
none
Statistics:
no data
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Dose descriptor:
NOAEC
Effect level:
700 mg/m³ air (nominal)
Basis for effect level:
other: overall effects, no adverse effects. Values for methyl salicylate.
Dose descriptor:
NOAEC
Effect level:
1 207 mg/L air (nominal)
Basis for effect level:
other: read-across value for homosalate
Critical effects observed:
not specified

No toxic signs and no macroscopic or microscopic effects were seen at necropsy following exposure to a saturated atmosphere for 7 hours per day, 5 days per week for 4 weeks.

Conclusions:
Methyl salicylate showed no evidence of toxicity by inhalation when tested at an effectively saturated concentration for 7 hours per day for four weeks. The highest tested concentration of methyl salicylate of 700 mg/m³ corresponds to 1207 mg/m³ of homosalate.
Executive summary:

4 female Alderley Park rats weighing an average of 200 g were exposed to a dynamic atmosphere (atmosphere continuously generated and passed through the exposure chamber) containing a saturated atmosphere (700 mg/m3) of methyl salicylate for 7 hours per day, 5 days per week for 4 weeks. Food and water were available ad libitum. Animals were weighed each day, and their condition and behaviour were recorded throughout the exposure period. Urine was collected overnight after the last exposure day for biochemical testing. Gross necropsy was conducted as well as microscopic examination of organs. Methyl salicylate at 700 mg/m3 (120 ppm), the maximum achievable atmosphere, did not cause any adverse effects (Gage, 1970).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
1 207 mg/m³
Study duration:
subacute
Species:
rat
Quality of whole database:
A suitable read-across study is available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Study duration:
subacute
Species:
rat

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

WoE was done based on the 28-day part of an oral OECD 422 study with homosalate and a chronic oral study with the read-across substance methyl salicylate. The two studies gave consistent results with NOAELs of 300 and 86 mg/kg bw/day, respectively. A read-across justification is provided as attachment to IUCLID section 13 respectively as appendix to the CSR

.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
WoE was done based on 28-day part of OECD 422 with homosalate and a chronic oral study with the read-across substance methyl salicylate

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
A 28-day repeated inhalation toxicity study is available with the read-across substance methyl salicylate

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
A 28-day repeated inhalation toxicity study is available with the read-across substance methyl salicylate

Justification for classification or non-classification

In a subacute study with homosalate, no severe toxic effects were observed at 300 mg/kg bw/day (which was the NOAEL in this study) and in a subchronic study with the read-across substance methyl salicylate, the NOAEL was 86 mg/kg bw/day (expressed as homosalate), while at a 5-fold higher dose histopathologic alterations of the pituitary and bone marrow without functional effects were observed. Based on these data, no classification and labelling according to the CLP (Regulation EC No 1272/2008) Specific target Organ Toxicity Repeat Exposure (STOT RE) or according to the DSD (Directive 67/548/EEC) is required.