Chlorimuron ethyl

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)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

See "Any other information on materials and methods" below

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

EC Number:

618-690-2

Cas Number:

90982-32-4

Molecular formula:

C15H15ClN4O6S

IUPAC Name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

Test material form:

solid

Remarks:

White

Details on test material:

95 to >99% purity

Specific details on test material used for the study:

Physical state: White powder; Analytical purity: 97.4%; Lot/batch No.: DPX-F6025-232; Stability under test conditions: The test substance appeared to be stable under the conditions of the study. No evidence of instability, such as a change in color or physical state, was observed

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/JHsd

Sex:

female

Details on test animals and environmental conditions:

Test animals: Source: Harlan Sprague Dawley, Frederick, Maryland, U.S.A.;
Age at study initiation: Approximately 9 weeks old;
Weight at study initiation: 20.5-22.1 g;
Housing: All animals were housed in solid bottom cages with appropriate bedding and nestlets toys as enrichment. During quarantine, animals were housed in pairs. After assignment to groups, and during the in-life phase of the study, animals were housed singly;
Diet: PMI® Nutrition International, LLC Certified Rodent LabDiet® 5002 ad libitum;
Water: All mice were provided tap water ad libitum;
Acclimation period: Quarantined for a minimum of 6 days;
Environmental conditions: Animal rooms were maintained at a temperature of 18-26ºC (64-79ºF) and a relative humidity of 30-70%; Photoperiod: Animal rooms were artificially illuminated (fluorescent light) on an approximate 12-hour light/dark cycle

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

0% (vehicle control), 5%, 25%, 50%, and 80%

No. of animals per dose:

5

Details on study design:

The objective of this study was to evaluate the potential of the test substance to produce a dermal sensitization response in mice using the local lymph node assay (LLNA). Five groups of 5 female CBA/JHsd mice were dosed for 3 consecutive days with 0% (vehicle control), 5%, 25%, 50%, or 80% of the test substance on both ears. Dimethylsulfoxide (DMSO) was used as the diluting vehicle. One group of 5 female mice was dosed for 3 consecutive days with 25% hexylcinnamaldehyde (HCA) in DMSO as a positive control. On test day 5 of the assay, mice received ³H-thymidine by tail vein injection and were sacrificed approximately 5 hours later. The cell proliferation in the draining auricular lymph nodes of the ears from the test substance groups was then evaluated and compared to the vehicle control group.

Positive control substance(s):

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

Statistics:

Significance was judged at p < 0.01. Lymph node dpm data were transformed to Log to obtain normality or homogenous variances.

Results and discussion

Positive control results:

A 25% concentration of the positive control, HCA, produced a dermal sensitization response in mice.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

0.82

Test group / Remarks:

5% group

Remarks on result:

not determinable

Results 2

Key result

Parameter:

SI

Value:

1.01

Test group / Remarks:

25% Group

Remarks on result:

not determinable

Results 3

Key result

Parameter:

SI

Value:

1.52

Test group / Remarks:

50% group

Remarks on result:

not determinable

Results 4

Key result

Parameter:

SI

Value:

0.84

Test group / Remarks:

80% group

Remarks on result:

not determinable

Cellular proliferation data / Observations:

Cellular proliferation (range in dpm)
Control group: 854.50 to 1614.50 dpm
5% group: 358.50 TO 1465.50 dpm
25% group: 683.50 to 1500.50 dpm
50% group: 1633.50 to 1920.50
80% group: 878.50 to 1093.50 dpm
Postive control group: 5300.50 to 8528.50 dpm

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on these data, the test substance is not a dermal sensitizer in mice.

Executive summary:

The objective of this study was to evaluate the potential of the test substance to produce a dermal sensitization response in mice using the local lymph node assay [LLNA] (OECD 429).

 

No statistically significant increases in cell proliferation measurements compared to the vehicle control group were observed at any test concentration. SIs of less than 3.0 were observed at all test concentrations of the test substance. Therefore, the EC3 value (the estimated concentration required to induce a threshold positive response, i.e., SI = 3) for the test substance under the conditions of this study was not calculable. A 25% concentration of the positive control, HCA, produced a dermal sensitization response in mice. Therefore, the LLNA test system was valid for this study. Under the conditions of this study, the test substance did not produce a dermal sensitization response in mice.