Cassava starch–konjac glucomannan biodegradable blend films: In vitro study as a matrix for controlled drug delivery

Abstract

AbstractCassava starch (ST)–konjac glucomannan (KGM) blend films were prepared, characterized, and their suitability as matrices for the sustained release of a model drug, theophylline (Thp) was investigated. Structural studies showed that there was a good compatibility between ST and KGM and also revealed the existence of strong interaction between Thp and the polymer blend. The thermal stability of the films did not alter on blending of the two polymers. The water vapor transmission rate (WVTR) and swelling capacity of the blend films were higher than that of the neat ST, while lower than that of the neat KGM films. The drug release was related to the pH of the medium and the relative humidity (RH) under which the films were stored. The drug release data fitted well to Higuchi kinetic model and the mechanism corresponds to anomalous transport with non‐Fickian kinetics corresponding to coupled diffusion/polymer relaxation. The rate of drug release was significantly (p<0.05) and positively correlated with the degree of erosion of the blend films. The study showed that the blend film with a composition, ST: 1.5 × 10−3 kg and KGM: 1.5 × 10−3 kg with 20% glycerol as plasticizer stored at a relative humidity in the range 11–53% was appropriate for the sustained release of the less water soluble drug, theophylline.