Abstract:Objective: To develop pulsed-release system of verapamil in the light of circadian rhythms of hypertensive patients. Methods: Factors affecting the lag time of the system were tested. Three swelling disintegrates (L-HPC,CMS-Na, CMC-Ca) of different contents were used. Various composition of out shell was tested through the uniform design and dealed with multiple regression. Two basic formulations with lag time 3 and 5h were decided. Results: The lag time 5h formulation: CMS-Na was the preferable disintegrant with a content of 15mg/tablet, out shell composition were chosen as following: PEG 6000 110mg, HCO 105mg, EVA 25mg each tablet, hardness 490kPa. Conclusion: A new press-coated tablet for the pulsed-release of drug after a programmable period of time is achieved in the in vitro dissolution test.