Using the direct compression method, sustained-release matrix tablets for once daily administration of nifedipine were developed.The nifedipine tablets were prepared with hydroxypropyl Me cellulose as basic matrix material.The dissolution of nifedipine from the tablets was evaluated as a formulation that had a sustained release over 24 h.The pharmacokinetic parameters of beagle dogs were investigated by the HPLC-MS/MS method.Compared with control marketed tablets, the relative bioavailability of the test tablets was calculatedThe pharmacokinetic parameters of the test tablets were similar with the reference tablets, which indicated that the test tablets possessed excellent sustained-release performance.Relative bioavailability of the test tablets to control was (100.9 ± 12.4)%.Statistics anal. showed that the release percentage of nifedipine from tablets in vitro was related to the drug absorption rate in vivo.The test nifedipine tablets could be an ideal 24 h sustained-release formulation.