1H,5H-Pyrazolo(1,2-a)pyrazol-1-one, 2,3-diamino-6,7-dihydro-, dimethanesulfonate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 September 2006 to 25 September 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): R0054002C, synonym IMEXINE OBH
- Physical state: beige to yellow powder
- Purity: 99.7%
- Impurities (identity and concentrations): not indicated
- Purity test date: 20 July 2006
- Lot/batch No.: R0054002C 013 L 001, synonym 0604070001
- Expiration date of the lot/batch: 01 August 2007
- Stability under test conditions: not indicated
- Storage condition of test material: at room temperature and under nitrogen gas

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest Saint Isle, France
- Age at study initiation: 9 weeks
- Weight at study initiation: 21.1 g +/- 1.1 g
- Housing: disposable crystal polystyrene cages
- Diet (e.g. ad libitum): SsniffR/M-H pelleted diet
- Water (e.g. ad libitum): tap water (filtered using a 0.22 micron filter)
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 30 to 70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

No. of animals per dose:

four

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

0, 2.5, 5, 10, 15, 18 %

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: A solution was obtained at the maximum concentration of 15% and the best homogeneous suspension was obtained at the concentration of 18%.
- Irritation: The test item was non-irritant in the preliminary test, whatever the concentration tested.
- Lymph node proliferation response: not evaluated.


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Lymph node cell proliferative responses were measured as described by Kimber and Dearman (1991).
- Criteria used to consider a positive response: The test item was considered as a skin sensitizer when the SI for a dose group is > 3.


TREATMENT PREPARATION AND ADMINISTRATION: On days 1, 2 and 3, a dose-volume of 25 µL of the control or dosage form preparations was
applied to the dorsal surface of both ears, using an adjustable pipette fitted with a plastic tip.
In order to avoid licking and to ensure an optimized application of the test materials, the animals were placed under light isoflurane anesthezia during the administration.
No massage was performed but the tip was used to spread the preparation over the application sites. No rinsing was performed between each application.

Positive control substance(s):

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

Results and discussion

Positive control results:

No unscheduled death occurred in the study. Hypoactivity was observed on day 6, in one female treated with the test item at the concentration of
2.5%.

Local irritation
On day 6, crusts were observed in 2/4 and 1/4 females treated with the test item at the concentrations of 15 and 18%, respectively.
A yellow coloration of the skin of the ears was noted in all the animals treated with the test item at the concentration of 15 or 18%.
No increase in ear thickness was observed in the animals of the treated groups.

Proliferation assay
No significant lymphoproliferation was noted at any tested concentration, while significant lymphoproliferation was observed with HCA at 25%.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: See table 1

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: See table 1

Any other information on results incl. tables

Table 1: Results of LLNA: Stimulation Index and Disintegration per minute

Sample Description Test or Control Group	Vehicle	2.5%	5%	10%	15%	18%	Positive control
Stimulation Index (SI)	-	0.80	1.74	1.56	2.51	1.84	5.92
Disintegration per minute and per group	537.42	432.42	936.89	837.19	1349.33	987.33	3179.63
Disintegration per minute and per node	67.18	54.05	117.11	104.65	168.67	123.42	397.45

 

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test item did not induce contact sensitization in the murine Local Lymph Node Assay.