Document Type : Research Paper
School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
Medical Biomaterial Research Center, Tehran University of Medical Sciences, Tehran, Iran
Shimi Pajohan Sabze Nikan, Tehran, Iran
Department of Civil, Chemical, Environmental, and Material Engineering (DICAM), Alma Mater Studiorum – University of Bologna, Bologna, Italy
Metoprolol has been widely used for controlling high blood pressure, preventing myocardial reinfarction, setting rate changes, setting heart rhythm, treatment of chronic angina and preventing excessive bleeding during surgery. The purpose of this research is formulation and manufacture of extended release tablets of metoprolol succinate that conform to all the in vitro physicochemical US Pharmacopoeia national formulary (USP32). For preparing the tablets, the hydrophilic HPMC(K100M) polymer was used in direct compression method. Release of metoprolol in phosphate buffer having pH=6.8 (USP32) was measured by HPLC. Also, using experimental correlation of diffusivity in buffer medium and Gurney-Lurie charts during tablet enlargement with time, diffusion coefficients of drug and partition coefficients were obtained at different time steps. The rate of drug release depends on the type, viscosity and polymer concentration. Drug release results over 20 hours for polymers of HPMC(K100M), HPMC(K4M), HPMC(K15M), polyethylene oxide, ethyl cellulose, Eudragit (RL100) were investigated and compared. The results demonstrated that HPMC(K100M) met the standards of USP32 very well and was superior over the other polymers tested.