Phthalic acid

Endpoint summary

Description of key information

Phthalic acid was shown to be no skin sensitizer in Guinea pigs.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No OECD Guideline or GLP defined. No test material concentration and dose defined.

Principles of method if other than guideline:

A modification of the Maguire method was adopted. The method derives from the "Split-adjuvant" technique, in which chemical allergen and Freund´s adjuvant are administered separately to the skin rather than as an emulsion.

GLP compliance:

not specified

Type of study:

other: Maguire method

Justification for non-LLNA method:

The test was performed before the LLNA method was validated.

Specific details on test material used for the study:

substance is called 1,2-benzene-dicarboxylic acid (compound No. 23)

Species:

guinea pig

Strain:

Hartley

Sex:

male

Route:

other: epicutaneous, no further data given

Vehicle:

no data

Concentration / amount:

no data

Route:

other: epicutaneous, no further data given

Vehicle:

no data

Concentration / amount:

no data

No. of animals per dose:

10

Details on study design:

Prior to conducting the sensitization test, the test material was applied as recieved on the clipped flanks of guinea pigs to determine if primary irritation would occur. If significant irritation was observed, dilutions of the test material were made in a suitable solvent. The highest concentration which did not caus primary irritation was used for the test.

The test procedure consisted of topical application of a 0.1 ml aliquot of the test material to the clipped and depilated backs of 10 guinea pigs for four times in 10 days. At the time of the third application, 0.2 ml of Freund´s adjuvant was injected intradermally at one point adjacent to the insult site. After a 2-week rest period, the guinea pigs were challenged on the clipped flanks with the test material on one flank and a solvent on the other flank. The challenge site was evaluated for erythema and edema at 24 and 48 hours. A moderate erythema and/or edema in two or more guinea pigs would be considered sufficient to classify the test material as a potential human skin sensitizer.

Positive control substance(s):

yes

Remarks:

Epichlorohydrin and diglycidyl ether of 2,2-di-(p,p'-hydroxyphenyl)propane

Reading:

rechallenge

Hours after challenge:

24

Group:

test chemical

Dose level:

no data

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no data

Remarks on result:

other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: no data. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.

Group:

positive control

Remarks on result:

other: diglycidiylether of 2,2-di-(p,p'-hydroxyphenyl)propane

Group:

negative control

Remarks on result:

other: Various chemical groups were evaluated for their skin sensitisation potential in guinea pigs. Therefore a sufficient basis for a negative control is available.

0 of 10 tested animals showed effects.

Interpretation of results:

GHS criteria not met

Executive summary:

In a modiefied method of the Maguire method the test procedure consisted of topical application of a 0.1 ml aliquot of the test material to the clipped and depilated backs of 10 Hartley guinea pigs for four times in 10 days. At the time of the third application, 0.2 ml of Freund´s adjuvant was injected intradermally at one point adjacent to the insult site. After a 2-week rest period, the guinea pigs were challenged on the clipped flanks with the test material on one flank and a solvent on the other flank. The challenge site was evaluated for erythema and edema at 24 and 48 hours. A moderate erythema and/or edema in two or more guinea pigs was considered sufficient to classify the test material as a potential human skin sensitizer. In 0/10 animals effects were observed, therefore the test substance was not found to be sensitising.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a modified method of the Maguire method the test procedure consisted of topical application of a 0.1 ml aliquot of the test material to the clipped and depilated backs of 10 Hartley guinea pigs for four times in 10 days. At the time of the third application, 0.2 ml of Freund´s adjuvant was injected intradermally at one point adjacent to the insult site. After a 2-week rest period, the guinea pigs were challenged on the clipped flanks with the test material on one flank and a solvent on the other flank. The challenge site was evaluated for erythema and edema at 24 and 48 hours. In 0/10 animals effects were observed, therefore the test substance was not found to be sensitizing (Rao, 1081).

This finding was supported by a skin sensitization test in female Hartley guinea pigs where the test substance also proved to be non-sensitizing (Sarlo, 1992).

Respiratory sensitisation

Endpoint conclusion

Additional information:

In a respiratory allergenicity test in female Hartley guinea pigs the test substance proved to be non-sensitizing (Sarlo, 1992).

Justification for classification or non-classification

Based on the available studies, no classification for sensitization according to EU Regulation is warranted.