4-[2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1 December 1998 to 5 January 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

other: Body responsible for the test

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study was conducted prior to the entry into force of 1907/2006 regulation.

Test material

Test material information

Constituent 1

Reference substance name:

4-[2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoic acid

EC Number:

429-790-9

EC Name:

4-[2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoic acid

Cas Number:

137281-39-1

Molecular formula:

Hill formula: C15 H14 N4 O3 CAS formula: C15 H14 N4 O3

IUPAC Name:

4-(2-{2-amino-4-oxo-3H,4H,7H-pyrrolo[2,3-d]pyrimidin-5-yl}ethyl)benzoic acid

Test material form:

solid: particulate/powder

Details on test material:

- Compound 202723
- Storage condition of test material: In the dark at ambient temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: A reputable UK based supplier

- Age at study initiation: less than 12 months
- Weight at study initiation: 295-358 grams
- Housing: aluminimum cages
- Diet: ad libitum supply of 'Guinea Pig Diet FD1' animal feed
- Water: ad libitum supply of domestic mains water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19 -20 °C
- Humidity: 35%
- Air changes (per hr): 15
- Photoperiod: 12 hour light/dark cycle (light hours 07:00-19:00)

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

water

Remarks:

distilled

Concentration / amount:

INDUCTION - Intradermal injections: 2% compound 202723 in vehicle (1:1) so final concentration in vehicle reported is 1%

Induction 2

Route:

epicutaneous, semiocclusive

Vehicle:

water

Remarks:

Distilled

Concentration / amount:

INDUCTION - Epicutaneous application: 50% compound 202723 in distilled water

Challenge

No.:

#1

Route:

epicutaneous, semiocclusive

Vehicle:

water

Remarks:

distilled

Concentration / amount:

Epicutaneous application: 50% compound 202723 in distilled water

No. of animals per dose:

Number of animals in test group: 10
Number of animals in control group: 5

Details on study design:

RANGE FINDING TESTS:
See Table 1 below for more information on the dose levels of compound 202723 included in the range finding study. Dose levels selected for induction phase were the highest that caused mild to moderate skin irritation and were also well tolerated systemically. Whilst dose levels selected for the challenge phase were the highest concentrations that did not cause irritation.

MAIN STUDY INDUCTION - Intradermal Injections
On Day 0 each animal was treated with 6 intradermal injections (see Table 2 for more information). Test site observations followed 24 hours after injection of test material.

MAIN STUDY INDUCTION - Epicutaneous Application
Six days after administration of the intradermal injections, 0.5ml of 10% sodium lauryl sulphate was applied to the treatment area of each animal (including control group). On the following day each animal was treated with one epicutaneous application to the scapular region under a Webril patch (s ee Table 3 for more information). The patches were removed after 48 hours and then the test sites w ere wiped with distilled water.
Test site observations followed 24 hours after removal of the patches.

MAIN STUDY CHALLENGE - Epicutaneous Application
Thirteen days after topical application. On the following day each animal was treated with test mate rial and vehicle topically on both flanks of the main study animals under 2 Webril patches (see Table
4 for more information). Patches were removed after 24 hours of exposure to the test material. Test site observations followed at 24 hours and 48 hours after removal of the patches.

SCORING SYSTEM
Scoring system used to assess any clinical observations recorded was as follows:
- No visible change Grade 0
- Discrete or patchy erythema Grade 1
- Moderate or confluent erythema Grade 3
- Intense erythema and swelling Grade 4

Challenge controls:

See "details on study design"

Positive control substance(s):

yes

Remarks:

2-mercaptobenzothiazole

Results and discussion

Positive control results:

A positive control was completed on 5 January 1999. Following challenge with mercaptobenzothiazole at a dose level of 25% w/v in maize oil, 100% of the test group animals and none of the control group animals reacted positively. These results demonstrate the ability of the test method to identify a mild/ moderate sensitiser.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

50%

No. with + reactions:

0

Total no. in group:

5

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

50%

No. with + reactions:

0

Total no. in group:

5

Any other information on results incl. tables

Maximum concentration not causing irritating effects in preliminary test 50%

 

Signs of irritation during induction - intradermal injection: discrete erythema noted in every animal.

Topical application: no erythemia reactions noted in any animal

Evidence of sensitisation of each challenge concentration: None

 

Other observations: None.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Substance not classified as skin sensitiser.

Executive summary:

The delayed contact hypersenstivity of compound 202723 was investigated by means of a Magnusson- Kligman Maximisation Test in guinea pigs.

The Magnusson-Kligman Maximisation test comprises of 2 procedures: an induction and a challenge procedure.The induction procedure consisted of exposure to the test material via 2 routes,intradermal injection and topical application. The animals were also exposed to an adjuvant material via intradermal injection. This was followed by a challenge exposure to the test material via topical application.

Two groups of animals were used in the study, a test and a control group.The test group contained 10 animals and the Control Group contained 5.During the induction procedure, the test group was exposed to 1% compound 202723 via intra dermal injection and 50% compound 202723 via topical application. The control group was exposed to vehicle, distilled water, only during this procedure.

 

Following challenge with 50% compound 202723, no positive response was noted in any of the test or control group animals. Under the conditions of the study, compound 202723 is considered not to be a sensitiser in guinea pigs.