Cyanuric acid

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:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Cyanuric acid

EC Number:

203-618-0

EC Name:

Cyanuric acid

Cas Number:

108-80-5

Molecular formula:

C3H3N3O3

IUPAC Name:

1,3,5-triazine-2,4,6-triol

Details on test material:

- Name of test material: Cyanuric acid
- Substance type: White powder
- Lot/batch No.: SPJ-16-184-C
- Storage condition of test material: Room temperature
- Stability under test conditions: Stable indefinately at room temperature

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/J

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley; Indianapolis, IN
- Age at study initiation: ~ 2 months
- Weight at study initiation: 21.6-26.8 g
- Housing: Housed individually in stainless steel cages, suspended with wire bottom
- Diet: PMI Feeds Inc. Formulab #5008; available ad libitum
- Water: Municipal water supply analyzed by TCEQ Water Utilities Division; available ad libitum
- Acclimation period: At least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C):19-21
- Humidity (%): 45-97
- Air changes (per hr): 10-12
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

100% undiluted; 50% and 25% w/v in 80% acetone; 20% olive oil

No. of animals per dose:

5

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: OECD 429
- Criteria used to consider a positive response: Stimulation index of ≥ 3.


TREATMENT PREPARATION AND ADMINISTRATION:
On days 1 ,2 and 3 each test animal received an open application of 25µL of an appropriate dilution (25% or 50%) of the test substance, or 100% test substance moistened with acetone:olive oil to the dorsum of both ears. On day 6 of the study all test and control animals were injected in the tail vein with 250µL of 0.01M phosphate-buffered saline (PBS), pH 7.4, containing 20 µCi of (methyl 11, 21 – 3H] Thymidine. Five hours after the injection, the animals were sacrificed, the draining auricular lymph nodes were excised and pairs from each animal were processed.
A single cell suspension was prepared by gentle mechanical disintegration through 200 mesh stainless steel gause. The cells were washed twice with an excess of PBS and precipitated with 5% trichloroacetic acid at 4C for 18 hours.

Positive control substance(s):

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

Statistics:

None applied

Results and discussion

Positive control results:

The positive control elicited a stimulation index of 9.5.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: Cyanuric acid produced a stimulation index of ≤ 3 in two of three groups of test animals. However, based on the severity of the response the positive results were considered indicators of borderline or mild skin sensitization potential.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Vehicle control: 668 Test group I (25%): 1390 Test group II (50%): 2244 Test group III (100%): 2500 Positive control: 6346

Any other information on results incl. tables

Table 1:Ratio derived for each test group based on group mean DPM

Animal group	Test substance concentration	Average count per mouse	Num. of mice in group	Test/vehicle control ratio
Vehicle control	NA	668	5	NA
Test group I	25%	1390	5	2.1
Test group II	50%	2244	5	3.4
Test group III	100%	2500	5	3.7
Positive control	NA	6346	5	9.5*

NA – not applicable

* - Positive control used to confirm animal sensitization potential and validate procedures 

The test substance produced a stimulation index (SI) of ≤3 in the 25% dose group and ≥3 in the 50% and 100% dose groups, which is considered a positive sensitization response. However, based on the low magnitude of the SI compared to that of the positive control, which is a moderate sensitizer, cyanuric acid is considered to have weak or mild sensitization potential in this LLNA test. There were no signs of excessive irritation at any test site

Applicant's summary and conclusion

Interpretation of results:

other: mild sensitiser

Conclusions:

Cyanuric acid produced a stimulation index of ≥ 3 in two groups of animals. However based on the severity of the response the positive results were considered indicators of borderline or mild skin sensitisation.