Thiolated and carboxymethylated <i>Cassia obtusifolia</i> seed mucilage as novel excipient for drug delivery: development and characterisation

Abstract

The objective of present work was to isolate the mucilage as polysaccharide from the seeds of Cassia obtustifolia and to modify the isolated polysaccharide chemically by thiolation and carboxymethylation to develop novel excipient for drug delivery application. The attempts were made to enhance mucoadhesive potential of Cassia obtustifolia seed mucilage by thiolation and to reduce the disintegration time in prepared tablets by carboxymethylation. Thiolation of Cassia obtustifolia seed mucilage was achieved by esterification with thioglycolic acid and thiol group content was measured by using Ellman’s reagent, whereas carboxymethylation was archived by etherification of Cassia obtusifolia seed mucilage with monochloroacetic acid and the degree of carboxymethyl substitution was determined by titrimetric method. Thiolation and carboxymethylation of Cassia mucilage was confirmed by, Fourier transform infrared spectroscopy (FT-IR), 1H NMR spectroscopy, differential scanning calorimeter (DSC thermogram) and by Zeta potential measurement. The findings demonstrated that there is significant improvement in bioadhesive and disintegration property via respective chemical modifications such as thiolation and carboxymethylation.