Sensitizing potential in mice, guinea pig and man of the preservative Euxyl (R) K 400 and its ingredient methyldibromo glutaronitrile

The allergenicity of the preservative Euxyl K 400 and its principal allerge n methyldibromo glutaronitrile (MDBGN) (1,2-dibromo-2,4-dicyanobutane) was investigated using 3 animal models; in mice, the local lymph node assay (LL NA) and in guinea pigs, the guinea pig maximization test (GPMT) and the cum ulative contact enhancement test (CCET) with a dose-response protocol inclu ded. Previous attempts to define the sensitization capacity of these chemic als have given conflicting results. For comparison, the frequency and cause s of positive patch test reactions to Euxyl K 400 and MDBGN were studied in patients referred to an occupational dermatology clinic. This investigatio n showed that Euxyl K 400 and MDBGN can give rise to contact allergy in man and that the relevant cases found mainly had similar exposure as non-occup ational cases. A contact allergenic potential could be detected for MDBGN i n 2 animal models, i.e., the CCET and the LLNA, and also for Euxyl K 400 in the LLNA. However, statistical analysis of the results from the GPMT with MDBGN failed to detect the sensitizing potential of this particular allerge n. The results indicate that to be able to detect the allergenic potential of Euxyl K 400 and MDBGN, a predictive test method with multiple topical ap plications at induction is required. It is therefore important that an inve stigator is aware of the possibility of using various predictive test model s for investigation of potential contact allergens.