Improvement of albendazole efficacy against enteral, but not against parenteral stages of Trichinella spiralis by preparing solid dispersions in polyvinylpyrrolidone.

A comparison was made, in the Trichinella/mouse model, of the anthelmintic effects of albendazole (ABZ) and ricobendazole (RBZ) formulated as solid dispersions in polyvinylpyrrolidone with regard to ABZ formulated as a suspension in carboxymethylcellulose. A solid dispersion significantly increased (p < 0.01) the efficacy of the drugs against intestinal preadult but not against migrating and muscle stages of the parasite. The anthelmintic efficacy of RBZ given as a solid dispersion was equivalent to (against preadult and encysted larvae) or significantly lower than (against migrating larvae) that of ABZ with the same formulation. The pharmacokinetic profiles of ABZSO as measured by HPLC showed no significant differences in the Cmax and AUC following administration of ABZ formulated as a suspension or solid dispersion although the Tmax was significantly lower for the dispersion.