Amylopectin-g-poly(N-vinyl-2-pyrrolidone): Synthesis, characterization and in vitro release behavior

•UV assisted grafting of N-vinyl-2-pyrrolidone on amylopectin.•Grafting was optimized by 3-factor, 2-level factorial design.•Metronidazole containing films of amylopectin-g-poly(NVP) were prepared.•Graft copolymer film showed prolonged release following Higuchi's release kinetics.

In the present study, amylopectin-g-poly(N-vinyl-2-pyrrolidone) was synthesized by UV-assisted grafting reactions. The effect of concentrations of amylopectin, N-vinyl-pyrrolidone and ammonium persulfate on the % grafting efficiency was studied using 3-factor, 2-level factorial experimental design. The graft co-polymer was characterized by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies. The concentrations of amylopectin, N-vinyl-2-pyrrolidone and ammonium persulfate were found to exert a significant synergistic effect on grafting efficiency. The optimized batch of graft co-polymer prepared using concentration of amylopectin (4%), N-vinyl-2-pyrrolidone (2%) and ammonium persulfate (10 mmol/L) had 83.16% grafting efficiency. On comparative evaluation of films of amylopectin-g-poly(N-vinyl-pyrrolidone) with amylopectin, the graft co-polymer film provided a prolonged release following Higuchi square release kinetics.