Encapsulation of antihypertensive drugs in cellulose-based matrix microspheres: characterizatio and release kinetics of microspheres and tableted microspheres

摘要

This study is an attempt to prepare microspheres loaded wlth two antl. hypertensive drugs viz., nifedipine (NFD) and verapamil hydrochloridl (VRP) using cellulose-based polymers viz., ethyl cellulose (EC) and cellulosl acetate (CA). Emulsification and solvent evaporation methods were optimizec using ethyl acetate as a dispersing solvent. The particles are spherical in shapl and have smooth surfaces, as evidenced by the scanning electron microscopy The microspheres were characterized for their particle size and distribution tapped density and encapsulation efficiency. Smaller sized particles with ~ narrow size distribution were produced with EC when compared to CA matrices. Molecular level drug distribution in the micro spheres was confirmec by differential scanning calorimetry. The micro spheres were directly com. pressed into tablets using different excipients. The drug release from CA wai faster than EC microspheres and, also, the VRP release was faster than NFD The excipients used in tableting showed an effect on the release as well as thc physical properties of the tablets.