Development and in vitro evaluation of sustained release multiparticulate tablet of freely water soluble drug

Blends of aqueous dispersion of a hydrophobic and hydrophilic polymer, namely Surelease®: hydroxypropyl methylcellulose (Surelease®: HPMC E15) were used as coating materials to control the drug release from coated pellets of the highly water soluble drug metoprolol succinate. Varying the polymer blends, ranges of drug release patterns were obtained at pH 6.8. The present study dealt with diffusion of drug through plasticized Surelease®/ hydroxypropyl methylcellulose (HPMC E15) films prepared by coating of drug and polymers onto non-pareil seeds using the solution layering technique. The release of metoprolol succinate from coated pellets was decreased with increased coating load of polymer. The optimized formulation was obtained by 32 full factorial design. The release profile revealed that the optimized formulation follows zero order release kinetics. The stability data showed no interaction for storage at 25oC and 60% relative humidity.