2-Butanol, 2-methyl-, lithium salt (1:1)

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2008-03-05 to 2008-03-11

Reliability:

1 (reliable without restriction)

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

2004/73/EC

Deviations:

no

Principles of method if other than guideline:

no other principles

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Age of animals : Young adult, 11-12 weeks old, age-matched within one week
Body weight range at starting : The weight variation in animals involved in the study did not exceed > 20 % of the mean weight.
Acclimatisation time: 35 days

Study design: in vivo (non-LLNA)

Induction

Concentration / amount:

NA

Challenge

Concentration / amount:

NA

No. of animals per dose:

NA

Details on study design:

NA

Challenge controls:

NA

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

5;10;25 % (w/v) (25µl)

No. of animals per dose:

4

Details on study design:

Three groups of female mice strain CBA/Ca Ola Hsd, each of five animals, received the appropriate formulation of LTA at concentrations 5 %, 10 % and 25 %. The negative control group received the solvent dimethyl formamide (DMF), the positive control group received. alpha.-Hexylcinnamaldehyde (HCA) dissolved in DMF at a concentration of 25%. Test sand control substance were applied on the external surface of each ear (25.mu.L/ear)for threeconsecutive days at the appropriate concentrations. On day 5, the cell proliferation in the local lymph nodes was measured by incorporation of
tritiated methyl thymidine (3H-methyl thymidine) and the values obtained were used to calculate stimulation indices (SI).

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

NA

Results and discussion

Positive control results:

The positive control substance alpha-Hexylcinnamaldehyde (HCA) was examined at a concentration of 25 % in DMF. Significant lymphoproliferative response (SI >= 3) was noted for the standard positive control (HCA) with an SI value of 8.5 demonstrating the appropriate performance of the assay. This value is not significantly different to the historic controls.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

Proliferation assays were conducted for all three concentrations of the test item (25 %, 10 % and 5 %). However, the 25 % group data were excluded from data analysis because the skin damage which persisted until study termination was an effect incompatible with the LLNA as it would have allowed an immuno-response against bacteria at the site of damaged skin. This immuno-response would include proliferation in the lymph node. No lymphoproliferative response (SI >= 3) was noted for Lithium-tert-amoxide (LTA) at the applied concentrations of 10 % or 5 %. Stimulation index values (SI) were 0.9 and 0.9 at concentrations of 10 % and 5 %, respectively.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: NA

Any other information on results incl. tables

Clinical signs and mortality:

No mortality or systemic toxicity was observed during the study Signs of minor irritation (red skin and some lesions) were observed in the 25 % test item treated group prior to the third treatment, it was visible at the base of the ears; on day 3 it was relatively mild and was not considered to be causing any animal suffering. However, the lesions did not recover; the skin surface remained broken until study termination. The pH values of formulations on the third day of dosing were measured and found to be 9.99, 9.48 and 7.71 for 25 %, 10 % and 5 % formulations, respectively.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information criteria: EU

Conclusions:

Under the conditions of the present assay Lithium-tert-amoxide, tested as a biologically compatible formulation up to the maximum feasible concentration (10 %) in an appropriate solvent was shown to have no sensitisation potential in the Local Lymph Node Assay.

Executive summary:

No mortality or systemic clinical signs and no treatment related effect on body weights were observed during the study. Irritation including skin integrity damage was observed in the 25 % test item treated group at the base of the ears of all animals and persisted until study termination.

The test material was considered to be a non-sensitiser.