3-Methoxy-3-methylbutyl acetate

Endpoint summary

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:

1992-07-02 to 1992-08-04

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study report includes a formal claim of GLP compliance and the methodology described is a recognised test for skin sensitisation, however the study cannot be considered reliable without restrictions, as no formal test guideline was followed, and no purity value for the test material was specified.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

Magnusson-Kligman Maximisation test: Magnusson B, Kligman AM (1969), J Invest Dermat, 52, 268 - 276.: A group of guinea pigs were exposed to the test material by a two-part induction period, followed by a challenge procedure. The induction period consisted of an Injection phase, in which the shaved flanks of the guinea pigs were injected with an adjuvant, the test material at 10% in paraffin oil, and a 50/50 mixture of the test material and adjuvant. The second phase of the induction involved provoking a mild inflammatory response on the animals' skin using 10% aqueous sodium lauryl sulphate (SLS). 24 hours after the exposure to SLS, the neat test material was applied directly to the injection site and held there for 48 hours. During each phase of the induction procedure, observations were made to assess any irritant effects.
The Challenge procedure was conducted two weeks after the topical induction procedure, and involved a further topical application of the test material for 24 hours.

GLP compliance:

yes

Remarks:

The study report includes a statement of GLP compliance signed by the Study Director, however the report does not include an independant certificate of GLP accreditation issued by a competent authority or similar document.

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Adequate data from an in vivo LLNA skin sensitisation study was available

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Limited, Darley Oaks, Newchurch, Burton-on-Trent, Staffordshire
- Age at study initiation: less than 1 year old
- Weight at study initiation: 428 - 507 g
- Housing: aluminium cage grid floor, absorbent paper lined tray
- Diet: ad libitum FD1 Guinea Pig Diet, supplied by Special Diets Services Limited, 1 Stepfield, Witham, Essex, CM8 3AD, supplemented with hay
- Water: ad libitum tap water
- Acclimation period: 8 days for dose ranging animals and main study 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 22°C
- Humidity (%): 55
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal and epicutaneous

Vehicle:

paraffin oil

Concentration / amount:

Dose ranging test - Injections at 100, 50, 25, and 10% in paraffin oil. Topical application at 100, 50, 25, and 10% in paraffin oil.
Main test, injection exposure - 10% in either paraffin oil or Freunds Complete Adjuvant.
Topical and challenge applications were performed using neat test material.

Route:

epicutaneous, semiocclusive

Vehicle:

paraffin oil

Concentration / amount:

Dose ranging test - Injections at 100, 50, 25, and 10% in paraffin oil. Topical application at 100, 50, 25, and 10% in paraffin oil.
Main test, injection exposure - 10% in either paraffin oil or Freunds Complete Adjuvant.
Topical and challenge applications were performed using neat test material.

No. of animals per dose:

20 for main test + 4 guinea pigs total for challenge dose ranging group.

Details on study design:

RANGE FINDING TESTS:
Injections were in the shaved scapular region and topical application was on the shaved flanks. Two guinea pigs were subjected to intradermal injections and a further 2 guinea pigs were exposed to topical application for 48 h of the test material at 4 different concentrations.
- Injections - 100%, 50%, 25% and 10% v/v in paraffin oil
- Topical application - 100%, 50%, 25% and 10% v/v in paraffin oil
The injection sites were assessed for irritation 24, 48 and 72 h after injection, and the topical application sites were assessed for irritation 24 and 48 h after patch removal.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: Injection exposure was conducted 7 days prior to topical application (6 days prior to SLS provocation of inflammatory response). Topical application remained in place for 48 hours.
- Test groups: Test group received injections of
(a) 0.10 mL Freunds Complete Adjuvant,
(b) 0.10 mL Test Material, and
(c) 0.10 mL of a 50/50 emulsion of Freunds Complete Adjuvant and test material.
Topical application used a 2 x 4 cm patch of chomatography paper charged with 100% test material.
- Control group: Doses as per the test group, but with paraffin oil in place of test material.
- Site: Hair was shaved from an area 4 x 6 am across the scapular region. Injections were given 3 in a line each side of and parallel to the mid-line in the shaved region.
- Frequency of applications: Single injected and topical applications.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 2 weeks after the start of the topical induction.
- Exposure period: 24 hours
- Test groups: Test and control groups were challenged both with patches of 100% test material, and with paraffin oil.
- Site: A 5 x 5 cm area of the left flank.
- Evaluation (hr after challenge): 24 and 48 hours.

Challenge controls:

The challenge procedure used patches treated with neat test material and paraffin oil.

Positive control substance(s):

yes

Remarks:

The sensitivity of this strain of guinea pig to a known sensitiser, 2,4-dinitro-chlorobenzene (DNCB), is checked at 6 monthly intervals.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0%

No. with + reactions:

3

Total no. in group:

20

Clinical observations:

One animal also gave a positive reaction to negative control patch (paraffin oil)

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0%. No with. + reactions: 3.0. Total no. in groups: 20.0. Clinical observations: One animal also gave a positive reaction to negative control patch (paraffin oil).

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0%

No. with + reactions:

2

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0%. No with. + reactions: 2.0. Total no. in groups: 20.0.

Group:

positive control

Remarks on result:

not measured/tested

None of the animals in the test group showed positive reactions to the challenge applications. Three of the animals in the control group, which had been induced only with the vehicle (paraffin oil) showed reactions to the test material during the challenge procedure. One animal in the control group showed a reaction to the vehicle in the challenge procedure.

Bodyweight gains recorded throughout the study were acceptable.

No clinical signs, other than skin reactions induced by treatment were noted.

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

There was no evidence from the test results that the test material is a sensitiser in Guinea Pigs.

Executive summary:

The sensitisation potential of a test material, MMB-Ac, was investigated by means of the Magnusson-Kligman Maximisation Test in guinea pigs.

Induction with MMB-Ac was at concentrations of 10% v/v in paraffin oil (injection) and 100% (topical). Challenge was at a concentration of 100% .

At challenge, none of the test group animals treated with MMB-Ac at a concentration of 100% showed a positive response. An irritant

response was noted in 3 of the control group animals to the test material with one of them also reacting positively to the vehicle, paraffin oil. There is no evidence from the test results that MMB-Ac is a sensitiser in guinea pigs.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A skin sensitisation study was conducted to determine the potential for the test material to cause skin sensitization. The study was conducted in compliance with GLP, and the methodology used, the Magnusson-Kligman Maximisation Test, is a well recognised test for this effect.

A test group and a control group, each of 20 Guinea Pigs, were exposed to the test material (or untreated vehicle, paraffin oil, in the case of the control group) by intradermal injection followed one week later by a topical application during the induction phase of the study. Three weeks after the commencement of the induction procedure, the challenge procedure was performed by topical application of test material and vehicle to all animals.

No positive reactions to the challenge procedure were seen in any of the test group animals. In the control group, three animals showed a reaction to the test material, and one to the vehicle.

On the basis of these results, there is no evidence of skin sensitisation by the test material.

Migrated from Short description of key information:

No evidence of sensitisation seen in Guinea Pigs (Magnusson-Kligman method).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Justification for classification or non-classification

In the Magnusson-Kligman Maximisation test, no evidence of skin sensitisation was observed. On the basis of this, there is no need for classification as a skin sensitizer.