A Classification Model for Allergic Contact Dermatitis

A classification model based on 36 compounds inducing allergic contact dermatitis and 36 non‐allergens was developed by the discriminant technique of two‐value multiple regression analysis. One outlier was observed and several of the compounds fell in the indeterminate region between the classes. Based on variable results of clinical data (human and animal), some overlap in the model was considered more reasonable than perfect separation. The descriptors in this model clearly imply intercellular transport (LogP derived) and various forms of binding (London forces [MR] and hydrogen‐bonding [HBA, HBD]) as part of the allergic contact dermatitis (ACD) response mechanism. In addition, substructure descriptors related to the epidermal reactivity of the ACD inducers were statistically important. These include directly reactive functional groups from haptens and metabolizable precursor groups of prohaptens. The model was developed from carefully selected compounds of diverse structure, representing a broad range of hapten and prohapten substructures without undue molecular complexity. Validation of the model is in progress on a broad range of molecular structures far beyond those used in construction.