The oral bioavailability and anthelmintic efficacy in mice of a new formulation of albendazole (ABZ) dissolved in a solution of hydroxypropyl-beta-cyclodextrin (HPCD) are compared with a conventional ABZ suspension of carboxymethylcellulose. Plasma concentrations of ABZ and albendazole sulphoxide (ABZ-SO), its active and main metabolite, were assayed by HPLC. The AUC(0- infinity ) and C(max) values obtained for both ABZ and ABZ-SO, after administration of the ABZ-HPCD solution were significantly higher (P<0.01) than those obtained from the ABZ suspension. Although, the differences between the ABZ and ABZ-SO-T(max) values were found not to be significant, regardless of the formulation. The anthelmintic activities against enteral (pre-adult) and parenteral (migrating and encysted larvae) stages of Trichinella spiralis were studied in mice. The ABZ solution was more efficient against pre-adult and encysted larvae than the ABZ suspension. The efficacy differences between both formulations against the migrating larvae, were found to be not significant (P<0.05). For the migrating parasite stage, there was a linear correlation between the anthelmintic activity and pharmacokinetical parameters with respect to the ABZ-AUC(0- infinity ) value. Meanwhile, for the muscular encysted parasite stage, better relationships were obtained for AUC(0- infinity ) and C(max) values from ABZ-SO, which had correlation coefficients of 0.996 and 0.987, respectively.