ε-caprolactam

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin Sensitization

Caprolactam (CAP) was tested similar to OECD guidelines in a guinea pig maximization test (challenge: 75% CAP in water), in a Buehler test (challenge: 75% CAP in water) and in a modified Buehler test (challenge: 25% CAP in water) and was considered to be not sensitizing (Industrial Health Foundation, 1991).

In the maximization test, twenty female animals were induced by intra-dermal application of 0.1 ml (3 %) of the test substance with FCA, followed by an epidermal application. Following a 14 day rest period, challenge was performed with an epidermal application of CAP (75%).

Slight to moderate patchy erythema and slight edema were observed 24h after challenge in the test group and in the negative control group (induction with water challenge with CAP). Dermal responses regressed at the second reading (48h), although still observable.

The skin effects in the control group animals after challenge treatment are an indication of an irritation reaction to the applied test concentration and therefore CAP is not considered to be a contact sensitizer under the test conditions chosen.

In the Buehler test, twenty female animals were induced by 3 epidermal applications to 0.4 ml (75% in water) of the test substance (on 3 consecutive weeks).

Again comparable reactions between animals previously induced with the CAP and challenge control guinea pigs were observed (slight to moderate patchy erythema and slight edema). An apparent increase in the occurrence of slight edema in the induced animals following challenge was addressed to the primary irritation of the test substance and not to a sensitization reaction. Summarized, CAP is not considered a contact sensitizer in guinea pigs under the conditions of this test.

A second, modified Buehler test was performed with a reduced CAP concentration (25%) in order to minimize the interference of dermal irritation with the sensitization read out. In a range finding assay 25% CAP was identified as the highest dose that produced only transient, minimal cumulative primary irritation following repeated (3x) applications over a one week period. With this test concentration only minimal dermal irritation (grades 0 to ±) was observed in both the test and negative control animals at challenge and rechallenge. Group mean dermal scores were also comparable, and thus, CAP was not considered to be a contact sensitizer under the test conditions chosen. 

 

In a skin-painting test (with 50% CAP) and following intracutaneous application (with 1% CAP), no sensitization reactions were observed with challenge concentrations of 50% CAP (BASF XII/315, 1966).

 

Apart from reliable studies, there are few human studies. CAP (5 %) produced no signs of irritation or indication of sensitization reactions when applied to the forearms of five volunteers (Goldblatt et al., 1954). In two of four cases with eczema on the legs after wearing nylon stockings a positive patch test (CAP 5 %) was reported (Jansson, 1959). Occupational contact dermatitis in a textile worker handling nylon fibers with an 18-month history of itchy, erythematous scaly eczema on the neck, chest and limbs was confirmed by patch testing (CAP 5 % aq) (Aguirre et al., 1995). Considering the rarely reported cases in human and negative results in reliable animal studies (with GLP), CAP does not require classification as skin sensitizer.

 

Migrated from Short description of key information:
Not sensitizing in guinea pig maximization test and Buehler test.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Respiratory sensitization:

In an Alarie-test with induction exposures on 5 subsequent days (max. aerosol concentration of 30 mg/l), no respiratory responses were detected, neither during the induction phase nor following a single challenge exposure of 30 mg/l (IHF, 1990).

Migrated from Short description of key information:
Not sensitizing in Alarie assay.

Justification for classification or non-classification

Not sensitizing in guinea pig maximization test, Buehler test and Alarie assay.