Development and Characterization of Chitosan-Poly (Vinyl Pyrrolidone) Blend Microspheres for Controlled Release of Metformin Hydrochloride

Chitosan-Poly (vinyl pyrrolidone), designated as CS-PVP, blend microspheres loaded with an anti-diabetic drug metformin hydrochloride (MH) were prepared using water-in-oil (W/O) emulsion method and used for controlled drug release studies. Microspheres were characterized by Fourier transform infrared spectroscopy (FTIR) to confirm the crosslinking reaction. Scanning electron microscopy (SEM) was also used to assess the surface morphology of particles prepared. The quantities of release of MH-loaded formulations were studied in terms of variation of blend composition and amount of crosslinking agent. DSC and XRD techniques indicated a uniform distribution of MH drug particles in microspheres, whereas SEM suggested the spherical structure of the microspheres with slight rough surface. The in vitro drug release indicated that the particle size and release kinetics depend upon blend composition, amount of cross-linking agent used, and amount of MH present in the microspheres. The prepared microspheres showed 50-82% encapsulation efficiency, which suggested that these IPN microspheres are suitable for controlled release of drugs up to 8 h.