Dibutyl carbonate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

July 2010

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

July 2012

Principles of method if other than guideline:

The study procedure was extended to include additional measures of lymph node response including lymph node cell count, lymph node weight and ear weight as an indicator of skin irritation to put the data into perspective.
The basis for these additions are described in:
- Kolle et al., Performance standards and alternative assays: practical insights from skin sensitization. Regul Toxicol Pharmacol. 2013 Mar; 65(2):278-85.
- Kolle et al., Further experience with the local lymph node assay using standard radioactive and nonradioactive cell count measurements. J Appl Toxicol. 2012 Aug; 32(8):597-607.
- Basketter et al., Experience with local lymph node assay performance standards using standard radioactivity and nonradioactive cell count measurements. J Appl Toxicol. 2012 Aug;32(8):590-6.

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl carbonate

EC Number:

208-816-0

EC Name:

Dibutyl carbonate

Cas Number:

542-52-9

Molecular formula:

C9H18O3

IUPAC Name:

dibutyl carbonate

Test material form:

liquid

Remarks:

colorless, clear

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: B16Q060201
- Purity test date: 2017-01-02

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature

Other:
pH value: 5

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Envigo, Netherlands
- Age at study initiation: 8 weeks
- Weight at study initiation: 17.6 - 20.8g
- Housing: single
- Diet (e.g. ad libitum): ad lib.
- Water (e.g. ad libitum): ad lib.
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12h/12h

Study design: in vivo (LLNA)

Vehicle:

methyl ethyl ketone

Concentration:

10%, 25%, 50%

No. of animals per dose:

5

Details on study design:

PRE-SCREEN TESTS:
- Compound solubility: Vehicle chosen because of good substance solubility
- # of animals per group: 2 females
- concentrations tested: 10%, 50%
- Irritation: none
- Systemic toxicity: none
- Ear thickness measurements: 10%: +3.5%, 50% +5%
- Erythema scores: no local findings
- lymph node weight stimulation index: 10%: 1.3, 50%: 1.8
- ear weight stimulation index: 10%: 0.87, 50%: 0.9

MAIN STUDY

TREATMENT PREPARATION AND ADMINISTRATION:
25µl per ear on 3 consecutive days

Positive control substance(s):

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

Results and discussion

In vivo (LLNA)

Results

Parameter:

EC3

Value:

16.9

Cellular proliferation data / Observations:

Stimulation index (3H-thymidine incorporation)
10%: 2.1
25%: 4.05
50%: 4.06

Lymph node cell count stimulation index
10%: 1.44
25%: 1.54
50%: 1.87

Lymph node weight stimulation index
10%: 1.44
25%: 1.72
50%: 1.76

Ear weights compared to control
10%: 102%
25%: 110%
50%: 106%

Any other information on results incl. tables

All test substance concentrations did not cause biologically relevant increases (SI > 1.25) in ear weights demonstrating the absence of relevant ear skin irritation, although a statistically significant increase in ear weights was noted at the 25% (but not at the 50%) concentration.

No signs of systemic toxicity were noted.

Very slight erythema and slight ear swelling was observed in the 50% dose group on day 2.

As one animal of the vehicle control group was identified as outlier, only the data of the remaining 4 animals were used for calculation of the mean values for the concurrent control group and for determination of the stimulation indices (SI) of the test item. Nevertheless, the calculation of the stimulation indices using the historical data for the vehicle MEK confirmed the results using the concurrent control group.

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria