Local and systemic effects of commonly used cutaneous agents: lifetime studies of 16 compounds in mice and rabbits.

A number of commonly used external agents were applied repeatedly on the skin of the mouse and rabbit. These chemicals, components of commercially available products included 4-hydroxyanisole, benzalkonium chloride, bromodeoxyuridine, iododeoxyuridine, 5-nitroacenaphthene, N-N-diethyltoluamide, hexachlorophene, para-aminobenzole acid, benzophenone, isopropylmyristate, pyrogallol, resorcinol and ethylhexanediol. Also tested were a commercial hairspray, a dandruff shampoo and an anti-dandruff agent. Local and systemic changes were studied and the tumour incidence compared with that of an effective carcinogen, 9,10-dimethylbenz(a)anthracene. The mice showed no local toxic changes or tumour formation and the systemic tumour incidence, i.e., tumours of the liver, lungs, lymphatic system and other organs, was similar to that of control animals. In rabbits, a number of proliferative, benign and malignant ear tumours were observed in the positive controls, thereby demonstrating the efficacy of this model. Local toxic changes were seen in benzalkonium- and hexachlorophene-treated animals, but no skin tumours. Four animals had uterine tumours. In addition, one lung and one kidney tumour, unrelated to the method of treatment, were seen.