Effect of carboxymethylation on physicochemical and release characteristics of Indian Palo starch

Abstract

Limited application of native starch has created the interest in the modification of starch to extend its asset for pharmaceutical application. An effort has been made to study the influence of carboxymethylation on morphological, physicochemical and drug release properties of wild Indian Palo (Curcuma angustifolia) starch. Carboxymethyl starches of different degree of substitution (0.046–0.256) were prepared using varying amount of monochloroacetic acid. The characteristic peaks at around 1600cm−1 confirmed the carboxymethylation of starch. Morphological studies showed that porous structure formed on the surface of the starch granules and degree of deformity was found to be increased with the increment in the degree of substitution. Amylose content was decreased with the increase in degree of substitution. The TGA data showed that the carboxymethyl starches were thermally stable. Swelling and solubility power was found to be improved with the increase in the temperature. Micromeritic properties of carboxymethyl starches proved its usefulness as excipients in tablet manufacturing. Release profile of paracetamol was found to be decreased with the increase in the degree of substitution, and this proves the suitability of carboxymethyl Indian Palo starch in sustained-release tablets.