Hydroxypropyl methylcellulose phthalate films reinforced with nanocrystalline cassava starch and intended its applications for colonic drug delivery

Abstract

Controlled-release drug delivery systems are crucial for improving therapeutic efficacy and patient compliance. Hydroxypropyl methylcellulose phthalate (HPMCP) films are promising candidates due to their film-forming properties and tunable release profiles. However, their mechanical properties can limit their applicability. This study aimed to assess the effect of addition of nanocrystalline cassava (NCS) starches to HPMCP films on the physicochemical and mechanical properties and the ability of films to control drug release rate. Reinforced HPMCP films with 2, 4 and 6 % w/w of NCS were characterized as a function of the microstructure, X-ray diffraction pattern, mechanical properties, and dissolution property. It was found that increasing starch amount induced an increase in heterogeneity of the film microstructure and crystallinity. The tensile strength of HPMCP films increased with addition of starches, while the elongation at break decreased. The lowest dissolution in pH 6.8 phosphate buffer solution was found for films containing NCS at 2 and 4 % w/w. For the application purposes, HPMCP containing different amounts of NCS was used to coat over diclofenac sodium tablets. The tablets coated with HPMCP containing 4 % w/w NCS showed the lowest drug release of 73.5 % in pH 6.8 phosphate buffer solution at 240 min. According to our results, the addition of NCS at adequate amount allowed to improve the mechanical properties of HPMCP films and to decrease the drug release rate which is important for the site-specific drug delivery process.