2,2-dimethylpropanethioamide

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Apr - Aug 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2,2-dimethylpropanethioamide

EC Number:

677-829-5

Cas Number:

630-22-8

Molecular formula:

C5H11NS

IUPAC Name:

2,2-dimethylpropanethioamide

Test material form:

solid: crystalline

Details on test material:

Purity or Composition 100.0 %

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

Female CBA/Ca (CBA/CaOlaHsd) strain mice were supplied by Harlan Laboratories UK Ltd., Oxon, UK. On receipt the animals were randomly allocated to cages. The animals were nulliparous and non-pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals were in the weight range of 15 to 23 g, and were eight to twelve weeks old.
The animals were individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes. Free access to mains tap water and food (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK) was allowed throughout the study.
The temperature and relative humidity were controlled to remain within target ranges of 19 to 25°C and 30 to 70%, respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was approximately fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06.00 to 18.00) and twelve hours darkness.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

Test 1
A group of five mice was treated with the test item at a concentration of 10% w/w in dimethyl formamide.
Test 2
three additional groups of five mice were treated with the test item at concentrations of 10%, 3% or 1% w/w in dimethyl formamide.

No. of animals per dose:

Test 1
A group of five mice was treated with the test item at a concentration of 10% w/w in dimethyl formamide.
Test 2
three additional groups of five mice were treated with the test item at concentrations of 10%, 3% or 1% w/w in dimethyl formamide.

Details on study design:

Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 10% w/w, this concentration was selected as the highest dose investigated in the main test of the Local Lymph Node Assay. A group of five animals was treated with 50 μl (25 μl per ear) of the as a solution in dimethyl formamide at a concentration of 10% w/w. A further group of five animals was treated with dimethyl formamide alone.
Based on the positive result obtained in Test 1, three additional groups of animals (Test 2) were treated with 50 μl (25 μl per ear) of the test item as a solution in dimethyl formamide at concentrations of 10%, 3% or 1% w/w. A further group of five animals was treated with dimethyl formamide alone.

Statistics:

Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose response relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett’s Multiple Comparison test was used and for non-homogenous datasets Dunnett’s T3 Multiple Comparison Method was used.
Probability values (p) are presented as follows:
p<0.001 ***
p<0.01 **
p<0.05 *
p>0.05 (not significant)

Results and discussion

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

0.86

Test group / Remarks:

1 Concentration (% w/w) in dimethyl formamide

Results 2

Key result

Parameter:

SI

Value:

1.01

Test group / Remarks:

3 Concentration (% w/w) in dimethyl formamide

Results 3

Key result

Parameter:

SI

Value:

1.08

Test group / Remarks:

10 Concentration (% w/w) in dimethyl formamide

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was considered to be a non-sensitiser under the conditions of the test.