Registration Dossier

Administrative data

Description of key information

Not sensitising (OECD 406, GLP, K, rel. 1)

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
Study period:
From 1999-01-18 to 1999-02-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study performed according to OECD test guideline No. 406 and in compliance with GLP with minor deviations. 1 animal in control and 1 animal in test group died during the study, therefore a total of 9 and 19 animals, in control and test group respectively, fulfilled the study. However, this deviation was not considered to have affected the classification of the test material as no animal showed sensitisation signs during the study.
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
Deviations:
yes
Remarks:
9 and 19 animals, in control and test group respectively instead of 10 and 20
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
Remarks:
9 and 19 animals, in control and test group respectively instead of 10 and 20
Principles of method if other than guideline:
not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
UK GLP Compliance Program (inspection date: 1998-03-23)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
At the time of study performance, the LLNA method was not adopted.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: David Hall Limited, Burton-on-Trent, Staffordshire, UK
- Age at study initiation: 8-12 weeks old
- Weight at study initiation: 345-446 g
- Housing: singly or in pairs in solid-floor polypropylene cages furnished with woodflakes
- Diet (e.g. ad libitum): ad libitum (Guinea Pig FD1 Diet, Special Diets Services Limited, Witham, Essex, UK)
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-22 °C
- Humidity (%): 43-53 %
- Air changes (per hr): approximately 15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: no data
Route:
intradermal
Vehicle:
arachis oil
Concentration / amount:
25% w/v
Day(s)/duration:
Day 0
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
100 % w/v
Day(s)/duration:
Day 7 / 48 hours
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
arachis oil
Concentration / amount:
75 % w/v (right flank) and 50 % w/v (left flank)
Day(s)/duration:
Day 21 / 24 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
8 preliminary test animals, 20 test animals, 10 control animals
Details on study design:
RANGE FINDING TESTS:
- Intradermal injections: 25%, 10%, 5%, and 1% v/v in arachis oil BP. 4 guinea-pigs. The highest concentration that caused only mild to moderate skin irritation, and which was well tolerated systemically was 25%.
- Topical induction and challenge: 100%, 75%, 50%, and 25% in arachis oil BP. 2 guinea-pigs. Undiluted test article was found to be non irritant when applied topically and was therefore selected for the topical induction phase of the main study.
- Topical challenge: 100%, 75%, 50%, and 25% in arachis oil BP. 2 guinea-pigs. The highest non-irritant concentration of the test material (75%) and one lower concentration (50%) were selected for the topical challenge stage of the main study

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2, intradermal injections and topical application
- Exposure period: 48h for topical application
- Test groups:
INTRADERMAL: 3 pairs of intradermal injection (0.1 mL) on Day 0 as follows:
- 1/ 50% v/v FCA/distilled water
- 2/ test substance 25% in arachis oil BP
- 3/ test substance 25% in 50:50 distilled water/FCA
The results of the topical induction sighting tests showed that the test material was non-irritant. Therefore, on Day 6, the nuchal region was clipped and shaved and a volume of 0.5 mL of sodium
laurylsulphate (10% w/w in petrolatum) was applied to the skin in order to provoke an inflammatory response. The treatment sites remained non-occluded.
TOPICAL: 7 days after intradermal injections, a filter paper patch (WHATMAN No.4: approximate size 4 cm x 2 cm), saturated with the undiluted test material was .applied to the prepared skin and held in place with a strip of surgical adhesive tape (BLENDERM: approximate size 5 cm x 3 cm) covered with an overlapping length of aluminium foil. The patch and foil were further secured with a strip of elastic adhesive bandage (ELASTOPLAST: approximate size 25 cm x 3.5 cm) wound in a double layer around the torso of each animal.
- Control group: similarly treated with the exception that arachis oil BP was topically applied instead of the test substance.
- Site: shoulder region
B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 21 days after test initiation
- Exposure period: 24 hours
- Test groups: 75% on the right flank, 50% on the left flank, v/v in arachis oil BP. Similarly treated than topical induction (patches 2cm x 2cm)
- Control group: similarly treated.
- Site: left and right flanks
- Concentrations: 100% and 50% v/v in ethanol
- Evaluation (hr after challenge): approximately 24 and 48 hours after patch removal.
Challenge controls:
None
Positive control substance(s):
no
Remarks:
(Historical control data on 2-Mercaptobenzothiazole are included)
Positive control results:
Summary of positive control data from the lab are available. The latest study was conducted between 1998-12-22 and 1999-02-05 with 2-Mercaptobenzothiazole. It was administered as a 10% concentration in arachis oil for the intradermal injections and a 50% concentration in acetone: PEG400 (70:30) for the topical induction. Challenge was conducted at concentrations of 50% and 25% in acetone: PEG400 (70:30). The incidence of sensitisation was 90% (9/10 animals).
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
19
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
19
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
19
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
19
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
other: latest historical control study results from the lab
Hours after challenge:
24
Group:
positive control
Dose level:
50% and 25% in acetone: PEG 400 (70:30)
No. with + reactions:
9
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Skin Reactions Observed After Intradermal Induction

Moderate and confluent to intense erythema was noted at the intradermal induction sites of all test group animals at the 24 and 48-hour observations. Discrete or patchy erythema was noted at the intradermal induction sites of all control group animals at the 24 and 48-hour observations.

Skin Reactions Observed After Topical Induction

Discrete or patchy to moderate and confluent erythema with or without very slight to slight oedema was noted at the topical induction sites of nineteen test group animals at the 1-hour observation. Discrete or patchy to moderate and confluent erythema with or without very slight oedema was noted at the topical induction sites of eleven test group animals at the 24-hour observation.

Other skin reactions noted at the topical induction sites of test group animals at the 1 or 24-hour observations were bleeding from the intradermal injection sites, small or large open wound, caused by animal scratching, hardened dark brown/black-coloured scab and small superficial scattered scabs. The reactions noted precluded the evaluation of erythema and oedema at the topical induction site of one test group animal at the 1-hour observation and eight test group animals at the 24-hour observation. No evidence of erythema or oedema was noted at the topical induction sites of control group animals at the 1 and 24-hour observations. Bleeding from the intradermal injection sites was noted in three control group animals at the 1-hour observation.

Skin Reactions Observed After Topical Challenge

No skin reactions were noted at the challenge sites of the test or control group animals at the 24 or 48-hour observations.

 

Bodyweight

Bodyweight gains of guinea pigs in the test group, between Day 0 and Day 24, were comparable to those observed in the control group animals over the same period.

 

Mortality

One test group animal was killed for humane reasons immediately after the 1-hour observation on Day 9, due to a large open bleeding wound on the test site, caused by the animal scratching. One control group animal was killed for humane reasons on Day 15, due to breathing difficulties. The absence of these animals was considered not to affect the purpose or integrity of the study.

Interpretation of results:
not sensitising
Conclusions:
The test material is not classified as a skin sensitiser under the test conditions.
Executive summary:

In a dermal sensitisation study performed according to the OECD test guideline No. 406 and in compliance with GLP, ST 08 C 98 was tested in male Hartley guinea-pigs using the Guinea-Pig Maximisation Test method (20 treated animals + 10 controls).

The preliminary study determined the concentration to be used for the induction and challenge phases of the main study.

 

ST 08 C 98 diluted in arachis oil BP at 25% (v/v) was administered by injection for intradermal induction. The results of the topical induction sighting tests showed that the test material was non-irritant. Therefore, on Day 6, 0.5 mL of sodium laurylsulphate (10% w/w in petrolatum) was applied to the skin in order to provoke an inflammatory response. Topical induction was performed with ST 08 C 98 as supplied, 7 days after intradermal injections. For the challenge, the test material was tested at 75% and 50% v/v in arachis oil BP.

 

90% animals gave positive response to challenge concentrations of the positive control, 2-Mercaptobenzothiazole (latest historical data). The test system was therefore considered to be valid.

 

No skin reactions were noted at the challenge sites of the test or control group animals at the 24 or 48-hour observations.

One test group animal was killed for humane reasons immediately after the 1-hour observation on Day 9, due to a large open bleeding wound on the test site, caused by the animal scratching. One control group animal was killed for humane reasons on Day 15, due to breathing difficulties. The absence of these animals was considered not to affect the purpose or integrity of the study.

Based on the overall sensitisation rate, ST 08 C 98 is not classified as a skin sensitiser according to the Regulation EC No. 1272/2008 (CLP) and to the GHS.

This study is considered as acceptable and satisfies the requirement for skin sensitisation endpoint.

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

A key study was identified (Safepharm, 1999, rel. 1). In this dermal sensitisation study performed according to the OECD test guideline No. 406 and in compliance with GLP, ST 08 C 98 was tested in male guinea-pigs using the Guinea-Pig Maximisation Test method (20 treated animals + 10 controls). The preliminary study determined the concentration to be used for the induction and challenge phases of the main study.

ST 08 C 98 diluted in arachis oil BP at 25% (v/v) was administered by injection for intradermal induction. The results of the topical induction sighting tests showed that the test material was non-irritant. Therefore, on Day 6, 0.5 mL of sodium laurylsulphate (10% w/w in petrolatum) was applied to the skin in order to provoke an inflammatory response. Topical induction was performed with ST 08 C 98 as supplied, 7 days after intradermal injections. For the challenge, the test material was tested at 75% and 50% v/v in arachis oil BP.

 

90% animals gave positive response to challenge concentrations of the positive control, 2-Mercaptobenzothiazole (latest historical control data). The test system was therefore considered to be valid.

 

No skin reactions were noted at the challenge sites of the test or control group animals at the 24 or 48-hour observations.

One test group animal was killed for humane reasons immediately after the 1-hour observation on Day 9, due to a large open bleeding wound on the test site, caused by the animal scratching. One control group animal was killed for humane reasons on Day 15, due to breathing difficulties. The absence of these animals was considered not to affect the purpose or integrity of the study.

Based on the overall sensitisation rate, ST 08 C 98 is not concidered to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Harmonised classification:

The substance has no harmonised classification according to the Regulation (EC) No. 1272/2008 (CLP).

Self classification:

Based on the available data no additional self-classification is proposed according to the CLP and to the GHS.

No data was available for respiratory sensitisation. However, this substance is not a skin sensitizer, therefore according to Figure R.7.3 -2 of the Chapter R.7 (V 4.1 - October 2015) the chemical is not considered as a respiratory sensitizer.