The bioequivalence of three sustained release nifedipine formulations designed in this laboratory, was assayed in rabbits by comparing their plasma time profiles to a reference (Adalat(R) retard). The analysis of data was performed by using the statistical moments as a measure of drug release. Results show a slowler absorption rate in the experimental formulations than in Adalat(R) retard, and not differences in the absorption extent. The composed one-compartment model, described for humans, showed to be also succesfull for rabbits.