Phosphoric acid, chromium(3+) salt (1:2.5)

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: read-across from constituent CrIII

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Studies on contact sensitivity to chromium in the guinea pig. The role of valence in the formation of the antigenic determinant.

Author:

Siegenthaler U, Laine A, Polak L

Year:

1983

Bibliographic source:

Journal of Investigative Dermatology 80 (1):44-47

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Existing data

Test material

Test material information

1

Reference substance name:

Cr III

Molecular formula:

Cr III

IUPAC Name:

Cr III

Details on test material:

CrCl3.6H2O or CrCl3

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: chromium chloride (Merck, Darmstadt, FRG)

Sex:

male/female

Details on test animals and environmental conditions:

T hey weighed about 350- 400 g when sensitization was begun. The animals were bred at the Institute for Biochemical Research, Fii Uinsdorf, Switzerland. T hey were fed on peUet d iet supplemented
ad libitum with water containing vitamin C.

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal

Vehicle:

not specified

Concentration / amount:

2 mg chromium chloride/l

Challenge

No.:

#1

Route:

epicutaneous, open

Vehicle:

not specified

Concentration / amount:

2 mg chromium chloride/l

No. of animals per dose:

10

Details on study design:

The sensit ization was done in the following manner: 5 injections of 0.2 ml each of emulsion containing 2 mg/ml of chromium chloride (Merck, Darmstadt, FRG) in FCA were given into the footpad and nape of the neck.
Animals were restimulated once a week by an intradermal injection of 25/-1g chromium chloride in 0.1 ml 0.15 M NaCl solu tion into the skin of the right fl ank. S imultaneously 0.02 ml of 0.5% chromium chloride solution in 1 % Triton X-100 were applied epicutaneously on the skin of the left flank. The boosting was continued weekly until a positive reaction to the hapten was observed. The animals were then challenged epicutaneously with both haptens and the skin inflammation evaluated 24 hr later according to an arbitrary scale: red, swollen = 2, red, contluent = 1, red spots = 0.5.

Challenge controls:

not applicable

Positive control substance(s):

not specified

Results and discussion

In vivo (non-LLNA)

Results

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

2 mg/L

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

Seven out of 10 guinea-pigs sensitized and boosted with chromium chloride responded to an epicutaneous challenge with chromium chloride.

Remarks on result:

positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

According to the results of the study, chromium trichloride can be considered to be a sensitizer to guinea pigs' skin.

Executive summary:

10 guinea pigs were exposed to 5 injections of 0.2 ml each of an emulsion containing either 2 mg chromium chloride/ml in Freund’s complete adjuvant (FCA) into the footpad and nape of the neck. The animals were restimulated once a week by intradermal injections of 25 µg of chromium trichloride. Simultaneously, 0.02 ml of 0.5% chromium trichloride in 1% Triton X-100 was applied epicutaneously to the skin of the opposite flank. The boosting was continued weekly until a positive reaction was observed. Four to six weeks after the positive skin reaction had emerged, the animals were challenged epicutaneously with both haptens, and skin inflammation was evaluated 24 h later. Seven out of 10 guinea-pigs sensitized and boosted with chromium trichloride responded to an epicutaneous challenge with chromium trichloride.