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Administrative data

Endpoint:
sub-chronic toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
publication
Title:
In vitro penetration and subchronic toxicity of alpha-Methyl-1,3-benzodioxole-5-propionaldehyde
Author:
Api, A. M., Lapczynski, A., Isola, D. A., Glenn Sipes, I.
Year:
2007
Bibliographic source:
Food und Chemical Toxicology 45 (2007) 702 -707

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)
GLP compliance:
not specified
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
α-methyl-1,3-benzodioxole-5-propionaldehyde
EC Number:
214-881-6
EC Name:
α-methyl-1,3-benzodioxole-5-propionaldehyde
Cas Number:
1205-17-0
Molecular formula:
C11H12O3
IUPAC Name:
3-(1,3-benzodioxol-5-yl)-2-methylpropanal
Details on test material:
- Appearance: Colourless to pale yellow clear liquid
- Stability under test conditions: Stable in acetonitrile and in the mobile phase. Protect from air
- Storage conditions of test material: At room temperature protected from light
- Handling conditions of test material: Under yellow light
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No. of test material: International, Flavors and Fragrances (Lot No. R-H120512)

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories; Portage, MI

Administration / exposure

Type of coverage:
semiocclusive
Vehicle:
water
Remarks:
reverse osmosis water
Details on exposure:
TEST SITE
- Area of exposure: dorsal area of the trunk, 5 cm²
- Time intervals for shavings or clipplings: the dorsal area of the trunk was clipped prior to administration of the first dose and then once lo twice weekly thereafter as needed.

TEST MATERIAL
- Amounts applied: 0.043-0.259 mL/kg bw/day

VEHICLE
- Amount applied: 0.259 mL/kg bw/day
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
6-7 h/day
Frequency of treatment:
6 days/week (for 13 weeks)
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Remarks:
control group
Dose / conc.:
50 mg/kg bw/day
Dose / conc.:
150 mg/kg bw/day
Dose / conc.:
300 mg/kg bw/day
No. of animals per sex per dose:
15
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: based on 17-day dose range finding study
- Post-exposure recovery period in satellite groups: 4 weeks

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily

DETAILED CLINICAL OBSERVATIONS: No data

DERMAL IRRITATION: Yes
- Time schedule for examinations: Daily

BODY WEIGHT: Yes
- Time schedule for examinations: Not specified

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data

FOOD EFFICIENCY: No

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Not specified

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Not specified
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: Not specified
- Parameters checked in Table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Not specified
- Animals fasted: No data
- How many animals: Not specified
- Parameters checked in Table 2 were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes (see Table 3)
Other examinations:
- organ weights
- reproductive assessment
Statistics:
Levene’s test was performed to test for variance homogeneity. In the case of heterogeneity of variance at p ≤ 0.05, transformations were used to stabilize the variance. Comparison tests look variance heterogeneity into consideration. One-way analysis of variance (ANOVA) was used if applicable to analyze body weights, body weight changes, feed consumption, continuous clinical pathology values, and organ weight data. If the ANOVA was significant, Dunnett's t-test was used for group comparisons. Group comparisons versus control were evaluated at the 5.0%, two-tailed probability level with correction for multiple comparisons. Only data collected on or after the first day of treatment were analyzed statistically.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Dermal irritation:
effects observed, treatment-related
Description (incidence and severity):
Test article-related dermal irritation was observed during the treatment phase of the study at all doses ≥ 50 mg/kg/day. Findings included slight to moderate erythema, slight to moderate edema, slight to moderate desquamation, and slight, moderate, or marked atonia and fissuring. The incidences of these effects were similar across the treated groups of either sex; however, findings were generally observed at an increased incidence and severity (i.e., moderate) as the dose increases. Microscopic findings of the skin included inflammation, thickening and abnormal comification of the epidermis, epidermal ulcers and erosions. An exudate accumulated on the epidermal surface, and there was eosinophilic infiltration. Following a 4-week recovery, the skin appeared normal macroscopically and microscopically except for minimal to slight superficial dermal fibrosis in animals given ≥ 150 mg/kg/day.
Mortality:
no mortality observed
Description (incidence):
No test item-related mortalities occurred over the 13-week study or during the 4-week recovery period in rats of either sex.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Mean body weight changes and terminal body weights did not differ between treated and control groups of either sex.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
Food consumption did not differ between treated and control groups of either sex.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
no effects observed
Haematological findings:
not specified
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
A non-dose related increase in glucose, total protein and globulin was observed as well as a non-dose related decrease in the A/G ratio and inorganic phosphorus. These findings were typically associated with inflammation. Many of the differences were not statistically significant because of individual variability within each group. In males, statistically significant total protein and globulin levels were mildly higher only at the low and mid-doses. Lower albumin-to-globulin ratios were observed at all doses, but were statically significant only at the low and high doses- Statistically significant lower inorganic phosphorus levels were observed for males treated with 50 mg/kg bw/day. In females, the only statistically significant difference was in glucose levels, which were higher for females treated with 150 mg/kg bw/day.
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
Absolute and relative organ weights did not differ between treated and control groups of either sex.
Gross pathological findings:
no effects observed
Description (incidence and severity):
Macroscopic observation of organs at necropsy detected no abnormalities.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not specified
Histopathological findings: neoplastic:
not specified
Other effects:
no effects observed
Description (incidence and severity):
Mean sperm count, total sperm count and sperm morphology did not differ with dose or between treated and control rats. Estrous cycles did not differ with dose or between control and test item treated rats.

Effect levels

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
for dermal toxicity
Effect level:
50 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
dermal irritation
Key result
Dose descriptor:
NOAEL
Remarks:
systemic toxicity
Effect level:
> 300 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No treatment-related systemic effects were observed.

Target system / organ toxicity

Key result
Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
The NOEL for dermal irritation was determined to be below 50 mg/kg bw/day and the NOAEL for dermal irritation was determined to be 50 mg/kg bw/Day. The NOEL as well as NOAEL for systemic toxicity was determined to be greater than 300 mg/kg bw/day.
Executive summary:

A dermal repeated dose toxicity study was performed equivalent to OECD guideline 411 in Sprague-Dawley rats. The test item was applied dermally once daily to male and female rats (15/sex/group) at 50, 150, or 300 mg/kg bw/day (0.043, 0.129, or 0.259 mL/kg bw/day applied neat to 5 cm² dorsal skin) for at least 90 consecutive days. A control group (15/sex) was given vehicle (reverse osmosis water) at 0.259 mL/kg bw/day for a similar duration. Rats were necropsied at the end of treatment (10/sex/group) or following a 4-week recovery period (5/sex/group). The following parameters were evaluated: dermal irritation, estrous cycle, ophthalmologic examinations, body weight, feed consumption, hematology, blood coagulation, serum chemistry, organ weights, macroscopic and histopathologic examinations, and male reproductive assessment. No test item related mortalities or effects on estrous cycles, ophthalmic exams, mean body weights, mean body weight change, feed consumption, absolute or relative organ weights, macroscopic observations or male reproductive morphology/function were observed. Test item related dermal irritation was observed across all dose levels with increased incidence and severity at 300 mg/kg bw/day. Dermal irritation that initially ranged from slight to marked improved to slight (≥ 150 mg/kg bw /day) or resolved completely (50 mg/kg bw/day) during the recovery phase.

Based on the findings in this study, it can be concluded that the NOEL for dermal irritation is below 50 mg/kg bw/day and the NOAEL for dermal irritation is 50 mg/kg/bw/day when applied undiluted to 5 cm² of the dorsal skin. The NOEL as well as NOAEL for systemic toxicity is greater than 300 mg/kg bw/day.