Improving the oral bioavailability of albendazole in rabbits by the solid dispersion technique

We have investigated the oral bioavailability of granules of albendazole, a drug used for treating echinococcosis in man, prepared by the solid disper sion technique. Rapid dissolution and supersaturation were observed when hydroxypropylmethy l cellulose and hydroxypropylmethylcellulose phthalate were used as carrier s in the solid dispersion. They inhibited the crystallization of albendazol e from the supersaturated solution and maintained an amorphous state for 8h . Gastric acidity-controlled rabbits were used to evaluate the variation in absorption after oral administration of the albendazole solid dispersion. For rabbits with low gastric acidity the bioavailability of orally administ ered albendazole in the granular form prepared by solid dispersion was more than three times that of albendazole in physical mixtures. These results suggest that the bioavailability of albendazole in solid disp ersions might be high even if there is a great variation in the gastric pH of patients.