Investigation on release of highly water soluble drug from matrix-coated pellets prepared by extrusion–spheronization technique

The objective was to formulate itopride HCl (ITP) extended release matrix-coated pellets by extrusion–spheronization and to investigate the influence of concentration and viscosity grade of different polymers on release of a highly water soluble drug. The matrix pellet formulations consisted of polymers (10–30%) like hydroxypropyl methylcellulose (HPMC K4M, K15M, and K100M), ethyl cellulose (EC-7 cps), microcrystalline cellulose (10–30%) and a fixed quantity of lactose (10%). The initial fast drug release from the matrix pellets was effectively controlled by coating with 5% ethyl cellulose (10 cps) dispersion. The dissolution studies of coated formulations were carried out at different pH, and data were analyzed for drug release kinetics. Scanning electron microscope was used to examine the surface morphology and cross section of pellets. Kinetics of all coated formulations were best explained by Higuchi model (R2 = 0.94–0.99). However, HPMC matrix-coated pellets (F1, F4 and F7) also followed Baker and Lonsdale model (R2 = 0.96–0.99), whereas, EC matrix-coated pellets (F10) followed zero-order kinetics (R2 = 0.99). Release mechanism of all coated formulations was non-fickian. Both uncoated and coated pellets were found to be spherical. Fourier transform infrared spectroscopy was conducted on the coated formulations and no drug–excipients interaction was found.