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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study run to a method comparable with current guidelines, no GLP.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Acceptable guinea pig maximisation test equivalent or simialr to OECD Guideline 406.
Species:
guinea pig
Strain:
not specified
Sex:
not specified
Details on test animals and environmental conditions:
None stated
Route:
intradermal and epicutaneous
Vehicle:
other: Paraffin oil (Intradermal Induction) and petrolatum (Topical Induction and Challenge)
Concentration / amount:
Intradermal Induction: 3.0%
Topical Induction: 15.0%
Challenge: 7.0%
Route:
epicutaneous, occlusive
Vehicle:
other: Paraffin oil (Intradermal Induction) and petrolatum (Topical Induction and Challenge)
Concentration / amount:
Intradermal Induction: 3.0%
Topical Induction: 15.0%
Challenge: 7.0%
No. of animals per dose:
10 animals per dose
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 10 for Intradermal Induction and 10 for Topical Induction
- Exposure period: Intradermal Induction: 1 day; Topica1 Induction: 48 h, occluded
- Test groups: 10 animals per group for two groups
- Control group: yes
- Frequency of applications: once daily
- Concentrations: 3.0% (in paraffin oil) and 15.0% (in petrolatum)

B. CHALLENGE EXPOSURE
- No. of exposures: 20
- Exposure period: 24 h, occluded
- Test groups: 10 animals per group for two groups
- Control group: yes
- Concentrations: 7.0 (in petrolatum)

No additional data
Challenge controls:
None stated
Positive control substance(s):
yes
Remarks:
isoeugenol
Positive control results:
The isoeugenol gave a 100% response to Guinea Pig.
Key result
Reading:
other: Challenge I
Hours after challenge:
48
Group:
test chemical
Dose level:
7.0% in petrolatum
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: other: Challange I. . Hours after challenge: 48.0. Group: test group. Dose level: 7.0% in petrolatum. No with. + reactions: 0.0. Total no. in groups: 10.0.
Key result
Reading:
other: Challenge II
Hours after challenge:
48
Group:
test chemical
Dose level:
7.0% in petrolatum
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
One animal appeared equivocal result.
Remarks on result:
other: Reading: other: Challenge II. . Hours after challenge: 48.0. Group: test group. Dose level: 7.0% in petrolatum. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: One animal appeared equivocal result..
Group:
negative control
Remarks on result:
other: No results provided for the negative control
Key result
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
The isoeugenol gave a 100% response to Guinea Pig.
Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test substance appeared to be not sensitizing in Guinea pig maximization Test.
Executive summary:

This Guinea pig maximization test was conducted according to a method which similar to OECD Guideline 406.

The test substance appeared to be not sensitizing in Guinea pig maximization Test.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

The test substance was determined not to be a contact sensitiser using the Magnusson-Kligmann method and the open epicutaneous test. However, it was reported positive for allergenicity in guinea pigs in the Draize test, the maximisation test and a test with Freund's complete adjuvant.

Supportive evidence from Opdyke (1976) showed no evidence of sensitisation in a maximisation test with 25 human volunteers. In this test a concentration of 4% in petrolatum was used. Furthermore, in a human patch test using 5% the test substance in vaseline, positive reactions were noted in 10 of 100 patients. Positive reactions occurred in patients with sensitivity to benzoic acid or vanillin.

Overall it is concluded that the test substance is not a skin sensitiser.


Migrated from Short description of key information:
Information available is limited to 3 maximisation tests (Anonymous, 1991) performed to the same protocol (intra-dermal induction and 3 epicutaneous challenges), but with different challenge concentrations. The test substance was negative at all concentrations tested. In addition, a test in humans is available (Opdyke, 1976), where 10 out-of 100 patients showed a skin reaction in a patch test and 0 out-of 25 volunteers were positive in a maximisation test. This test indicates that the test substance does not induce skin sensitization. Positive results in a second maximization test, a draize test and an FCA test (Klecak, 1975) could not be evaluated properly because of incomplete information on the concentrations used for induction and challenge.

Justification for selection of skin sensitisation endpoint:
This study was carried out according to a reliable method which similar to OECD 406 using guinea pig.

Respiratory sensitisation

Link to relevant study records
Reference
Endpoint:
respiratory sensitisation: in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Publication is well documented, only the part related to exposure to the test substance is taken into account, non GLP
Qualifier:
no guideline followed
Principles of method if other than guideline:
Four-week-old male Hartley guinea pigs were intraperitoneally injected with 1 mL of an NaCl solution containing 100 μg ovalbumin (OA). These animals and not-pre-treated control animals were then exposed to the test substance (500 ppb) for 4 wk (6 h/d, 5 d/wk) . At the end of exposure, GPs were challenged with an OA aerosol ( 0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL) .
GLP compliance:
not specified
Species:
guinea pig
Strain:
Hartley
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River France
- Age at study initiation: Four-week-old
- Weight at study initiation: 414.4 ± 24.6 g
- Housing: Between exposures, four animals were housed per cage in suspended Plexiglas cages fitted with dust-free bedding.
- Diet (e.g. ad libitum): Animals were not fed during exposure but had access to food and water ad libitum between each exposure period.
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 7 d

No additional data available
Route of induction exposure:
other: not applicable
Route of challenge exposure:
inhalation
Vehicle:
other: NaCl solution
Concentration:
500 ppb, 2.2 mg/m3
No. of animals per dose:
8 males
Details on study design:
Four groups of eight guinea pigs were used:
Group 1. Air-exposed control.
Group 2. Air-exposed ovalbumin-sensitized.
Group 3. Test substance-exposed.
Group 4. Test substance-exposed ovalbumin-sensitized.
Animals were acclimated for at least 7 d before the experiment started. At d 0 and d 1, intraperitoneal injections of OA (groups 2, 4) or NaCl (groups 1, 3) were performed. At d 21, sensitization was determined (intradermal reaction) after OA provocation. Aldehyde exposure lasted from d 0 to d 26. Assessment of respiratory function parameters took place both before and after OA provocation, 3 d after the end of exposure (d 29). On the day after (d 30), animals were sacrificed by intraperitoneal injection of pentobarbital sodium in order to evaluate the inflammatory and atopic responses.
Positive control substance(s):
not specified
Negative control substance(s):
other: Air-exposed
Results:
No allergic reactions were noted in nonsensitized GPs challenged with OA. Therefore, all results from control GPs have been pooled.

Characteristics of sensitized guinea pigs:
Increased Penh reflecting enhanced bronchoconstrict ion.
Changes in pulmonary histology reflecting an irritation of the respiratory tract.
Increased number of eosinophils in blood.
Increased number of inflammatory cells (macrophages, neutrophils, and eosinophils) in BAL.
Increased levels of proteins in BALF reflecting an alteration of vascular and epithelial permeability of the respiratory tract.
Increased levels of the bronchoconstrictor lipid mediator LTC4/D4/E4.
Positive control results:
No information provided
Negative control results:
In guinea pigs treated with the test substance, ovalbumin (OA) provocation induced no modifications in respiratory functions.

Mortality, Clinical Signs, and Body Weights: Exposure to the test substance did not induce any mortality.

Respiratory Functions: In control GPs, ovalbumin (OA) provocation induced no modifications in respiratory functions.

Histopathology: For test substance-exposed GPs, histological examination of nasal cavities revealed a slight irritation (metaplasia/hyperplasia) of the respiratory epithelium for nonsensitized GPs.Histological examination of the trachea and lungs showed a slight irritation of respiratory epithelium for nonsensitized GPs.

Blood Parameters: No effects on eosinophils, monocytes, lymphocytes, neutrophils, and basophils in test substance treated non-sensitized guinea pigs. In nonsensitized GPs, the test substance induced significant reduction of triglycerides.

Interpretation of results:
not sensitising
Conclusions:
After exposure to the test substance a challenge with OA did not induce reactions related to respiratory sensitization.
In pre-sensitized animals a decrease both in OA-induced bronchoconstriction and in eosinophil and neutrophil numbers in BAL, an increase in the bronchodilatator mediator prostaglandin E2 (PGE2), and a decrease in the bronchoconstrictor mediators LTC4/D4/E4 was reportedafter exposure to the ets substace.
Executive summary:

Four-week-old male Hartley guinea pigs were exposed to the test substance (500 ppb) for 4 wk (6 h/d, 5 d/wk) . At the end of exposure, GPs were challenged with an OA aerosol ( 0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL) .

Exposure to the test substance did not lead to a allegic reaction after the challenge with OA on any of the parameters investigated.

In the nasal cavities slight irritation (metaplasia/hyperplasia) of the respiratory epithelium was observed. Histological examination of the trachea and lungs showed a slight irritation of respiratory epithelium for nonsensitized GPs.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Guinea pigs were exposed via inhalation to the test substance for 4 weeks (2.2 mg/m3) and than challenged with ovoalbumine. No allergic response to this challenge was reported. The only effects found were related to irritation of the respiratory tract epithelium.


Migrated from Short description of key information:
Guinea pigs were exposed via inhalation to the test substance for 4 weeks (2.2 mg/m3) and than challenged with ovoalbumine. No allergic response to this challenge was reported. The only effects found were related to irritation of the respiratory tract epithelium.

Justification for selection of respiratory sensitisation endpoint:
Only one study available and this is considered as reliable.

Justification for classification or non-classification

Based on the data available and read-across to benzoic acid it is concluded that the substance does not need to be classified for skin sensitisation and respiratory sensitization according to DSD and CLP.