p-toluic acid

Endpoint summary

Description of key information

Under the conditions of this study, p-toluic acid was shown to be sensitising to human skin

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

A small quantity of each test substance was placed on the wetted (tap water) central gauze portion of 1 1/2-inch-square BandAid before application to a nonhairy region of the upper back. Strips of Dermicel hypoallergenic tape were used to occlude, cover and secure the patches. The patches were applied to the same areas on Mondays, Wednesdays and Fridays for 3 weeks ( 9 applications in total) for 24 hr and then removed by the subjects themselves, except for the first two occasions when the investigators removed the patches. The subjects did not expose their backs to sunlight during this procedure. Residual powder was gently removed from the skin with the soft alcohol pads. The reactions were graded and recorded during each visit. An additional visit for grading and observation took place on Monday of the 4th week.

Challenge applications were performed on Monday of the 6th week following the commencement of the sensitization procedure. Patches were applied to a previously untested area of the of the upper back skin using the method described above, except that they were left in situ for 48 hr before removal. The reactions were graded shortly after patches removal and then at 96 and 144 hr after application.
Additional 48 hr challenging applications were performed on certain subjects following the same procedures.

GLP compliance:

no

Type of study:

Draize test

Justification for non-LLNA method:

Human study.

Species:

other: Human

Sex:

not specified

Route:

epicutaneous, occlusive

Vehicle:

other: polystyrene or petrolatum

Concentration / amount:

p-toluic acid, 50% in polystyrene, and o-toluic acid, 50% in polystyrene

Day(s)/duration:

2

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: polystyrene powder and petrolatum

Concentration / amount:

p-toluic, o-toluic and m-toluic acids, all three isomers at concentrations of 50% in polystyrene powder, 5% in petrolatum, and 1% in petrolatum.

Day(s)/duration:

4

Adequacy of challenge:

other: Reactions were observed in all 4 subjects to all three isomers,

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1
- Exposure period: 2 days
- Test groups: 1
- Control group: none
- Site:
- Frequency of applications: once
- Duration:
- Concentrations: 50%

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 4
- Exposure period: 4
- Test groups: 1
- Control group: none
- Site:
- Concentrations:
- Evaluation (hr after challenge): 18 days

OTHER:

Challenge controls:

none

Positive control substance(s):

no

Positive control results:

not applicable

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

4

Total no. in group:

10

Clinical observations:

Five of the subjects became sensitized to p-toluic. Sensitization reactions to p-toluic acid occurred days 15-18. In some subjects the challenge reactions were severe and necessitated removal of the patches before completion of 48-hr application time.

Remarks on result:

positive indication of skin sensitisation

Group:

negative control

Remarks on result:

not measured/tested

Group:

positive control

Remarks on result:

not measured/tested

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

Under the conditions of this study, p-toluic acid was shown to be sensitising to human skin.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitisation study in humans returned a positive result. Therefore this substance will be classified as a skin sensitiser; Skin sens 1.