Synthesis and characterization of novel carboxymethyl Assam Bora rice starch for the controlled release of cationic anticancer drug based on electrostatic interactions

Carboxymethyl Assam Bora rice starch (CM-ABRS) was chemically synthesized in non-aqueous medium with the optimum degree of substitution (DS) of 1.23, and physicochemically characterized by FT-IR, DSC, XRD, and SEM analysis. Comparative evaluation of CM-ABRS with native starch (ABRS) for powder flow characteristics, swelling index, apparent solubility, rheological properties, textural properties, and mucoadhesive studies were carried out. The aim of the current work was to investigate the potential of CM-ABRS as a novel carrier for the water-soluble chemotherapeutic, doxorubicin hydrochloride (DOX). Formation of drug/polymer complex (DOX-CM-ABRS) via electrostatic interaction has been evaluated for the controlled release of DOX in three different pH media (phosphate-buffered saline (PBS), pH 7.4, 6.8, and 5.5). In vitro drug release studies illustrated faster release of drug in PBS at pH 5.5 as compared to pH 6.8 and pH 7.4, respectively, indicating the importance of pH-sensitive drug release from the DOX-CM-ABRS complex in malignant tissues.