Potentiation of anthelmintic efficacy by the combination of alkylresorcinols.

Lamson et al. (1-8) carried out extensive studies on the anthelmintic activity of a large number of alkylhydroxybenzenes and found that substances which apparently act through the cuticle of ascaris were ineffective when their melting points were too high. Harwood (9) demonstrated that if such chemicals were kept in the liquid phase by adulteration with certain organic liquids, their in vitro ascaricidal properties were heightened. Considering these reports which suggest a close relationship be tween the anthelmintic effect and melting points of these substances, the present au thors attempted to increase the anthelmintic efficacy by combining certain alkylresor cinols with comparatively slight irritant action. The present paper gives evidence for the potentiation of in vitro and clinical efficacy by the combination of such chemicals, and describes observations on the toxi city and local irritant properties. Certain physical properties arising from such a combination, were studied in order to elucidate the mechanism of their synergistic effect.