Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 August 2010 – 12 October 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted according to EC and OECD test guidelines, and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2011

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
The study report included a current certificate of GLP compliance for the test facility, issued by the MHRA.
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: Off-white powder
- Storage condition of test material: aprox. -20 degrees in the dark.

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan UK Ltd
- Age at study initiation: Approximately 8 to 12 weeks of age prior to dosing on Day 1.
- Weight at study initiation: 17.4 to 20.6 g.
- Housing:The animals were housed in pairs in polycarbonate cages with woodflake bedding. The mice were also given Nestlets and a plastic shelter for environmental enrichment.
- Diet (e.g. ad libitum): The animals were allowed free access to a standard pelleted rodent diet (Rat & Mouse No. 1 Maintenance diet).
- Water (e.g. ad libitum): Potable water taken from the public supply was freely available via polycarbonate bottles fitted with sipper tubes.
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 23°C
- Humidity (%): 40 to 70%
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light


IN-LIFE DATES: From: 19 August 2010 (date of animal allocation to groups) To: 11 October 2010

Study design: in vivo (LLNA)

Vehicle:
dimethylformamide
Concentration:
0 (Dimethylformamide control), 1, 2.5, 5 and 10% w/v
No. of animals per dose:
4
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: Very thick suspensions were formed at 25% and 50% (w/v) in acetone:olive oil (4:1 (v/v), which were too thick for administration using a micropipette. In dimethylformamide, the test substance formed a pale brown solution at 50% (w/v) which was satisfactory for dose administration.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: The test substance is regarded as a sensitizer if at least one concentration of the test substance
results in a three-fold greater increase in 3HTdR incorporation compared to control values. (3HTdR = 3H-methyl Thymidine).
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
The results for this study included one concentration which had an SI greater than 3 and one concentration which had an SD of less than 3, therefore the EC3 value was calculated according to the following formula:
EC3 = c+[(3-d)/(b-d)](a-c)
a=concentration giving SI greater than 3, b=SI at concentration a, c=concentration giving SI less than 3, d=SI at concentration c.

Results and discussion

Positive control results:
The stimulation index for the positive control substance (HCA) was 7.5, which demonstrates the validity of this study

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: The test/control ratios obtained for 1, 2.5, 5 and 10% w/v test substance were 1.3, 2.3, 5.0 and 9.4 respectively.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see Remark
Remarks:
Control (DMF): 807.9 (=100.99 dpm/node, 8 nodes) 1% (w/v): 1017.2 (=127.15 dpm/node, 8 nodes) 2.5% (w/v): 1851.1 (=231.39 dpm/node, 8 nodes) 5% (w/v): 4074.3 (=509.29 dpm/node, 8 nodes) 10% (w/v): 7605 (=950.63 dpm/node, 8 nodes) HCA (positive control): 6021.3 (=752.66 dpm/node, 8 nodes)

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
The test substance is regarded as a potential skin sensitizer.
Executive summary:

A localised lymph node assay (LLNA) study was conducted by Huntingdon Life Sciences, UK, to determine the potential for skin sensitization of the test substance. The study was conducted according to OECD 429 and EEC B.42 Test Guidelines, and was performed in compliance with GLP. The test substance is regarded as a sensitizer if at least one concentration of the test substance results in a three-fold greater increase in 3HTdR incorporation compared to control values.

The test substance was found to generate a test/control ratio greater than 3 at two of the concentration tested (5 and 10% (w/v)), and so the test substance was considered to have the potential to cause skin sensitization (delayed contact hypersensitivity).