4'-chloro-2',5'-dimethoxyacetoacetanilide

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:

other: Well performed GLP and OECD guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

4'-chloro-2',5'-dimethoxyacetoacetanilide

EC Number:

224-638-6

EC Name:

4'-chloro-2',5'-dimethoxyacetoacetanilide

Cas Number:

4433-79-8

Molecular formula:

C12H14ClNO4

IUPAC Name:

N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutanamide

Details on test material:

- Name of test material (as cited in study report): Naphtol AS IRG TTR

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

Source: Harlan Netherlands, B.V. Postbus 6174, NL - 5960 AD Horst / The Netherlands
Number of animals for each pre-test (non GLP): 2 females
Number of animals for the main study: 16 females
Number of animals per group 4 females (nulliparous and non-pregnant)
Number of test groups: 3
Number of control (vehicle) group: 1
Age 8-12 weeks (beginning of acclimatisation)
Identification: Single caging. The animals will be distributed into the test groups at random and identified by cage number
Acclimatisation: Unter test conditions after health examination. Only animals without any visible signs of illness will be used for the study
Housing: single
Cage Type: Makrolon Type 1, with wire mesh top
Bedding: granulated soft wood bedding
Feed: pelleted standard diet, ad libitum
Water: tap water, ad libitum
Environment: temperature: 22 +/- 3 °C
rel. humidity approx: 30-83 %
artificial light: 6 a.m. - 6 p.m.

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

Doses: 0 (control group), 5, 10, 25 % (w/v, in DMSO)

No. of animals per dose:

4 per dose group

Details on study design:

For determination of the highest non-irritant and technically applicable test item concentration, a pretest was performed on two mice with concentrations of 2.5, 5, 10 and 25 % (w/v). The top dose of the test item is the highest technically achievable concentration whilst avoiding systemic toxicity an excessive local irritation.

The proliferative response of lymph node cells is expressed as the number of radioactive disintegrations per minute per lymph node (DPM/node) and as the ratio of 3HTdR incorporated into lymph node cells of test lymph nodes relative to that recorded for control lymph nodes (stimulation index: S.I.).

A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentrations resultes in 3-fold or greater increase in incorporation of 3HTdR compared to the concurrent control, as indicated by the stimulation index (S.I.)

Positive control substance(s):

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

Statistics:

Statistical analysis was conducted for assessment of the dose-response relationship and the EC3 value was calculated according to the equation
EC3 = (a-c)[3-d)/(b-d)]+c with EC3 is the estimated concentration of the test item required to produce a 3-fold increase in draining lymph node cell proliferative activity; (a, b) and (c, d) are the coordinates of the two pair of data lying immediately above and below the S.I. (stimulation index) value of 3 on the LLNO dose response blot

Results and discussion

Positive control results:

April 2004: EC3 = 6.3%
October 2004: EC3 = 9.9%

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: 5%: 1.7 10%: 1.8 25%: 1.3

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: DPM per lymph node: Control Group : 389.6 5%: 660.6 10%: 701.8 25%: 512.7

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test item Naphtol AS IRG TTR was found to be not a skin sensitiser in this assay.

Executive summary:

In the study the test item Naphtol AS IRG TTR dissolved in DMSO was assessed for its possible contact allergenic potential.

For this purpose a local lymph node assay was performed using test item concentrations of 5 %, 10 %, and 25 %.

The animals did not show any clinical signs during the course of the study and no cases of mortality were observed.

In this study Stimulation Indices (S.I.) of 1.7, 1.8, and 1.3 were determined with the test item at concentrations of 5.0, 10.0, and 25.0 % (w/v) in DMSO.

The test item Naphtol AS IRG TTR was found to be not a skin sensitiser in this assay.