Effect of carboxymethylation on rheological and drug release characteristics of Terminalia catappa gum

The carboxymethylation of galactomannans, arabinogalactans, arbinoxylan, etc is known to modify solubility, swelling index, rheological behaviour, powder characteristics, etc. Therefore, an attempt had been made to study the effect of carboxymethylation on Terminalia catappa (TC) gum. For this, modified Williamson synthesis reaction was utilized employing Quality by Design (QbD) approach. Grafting of carboxymethyl group on Terminalia catappa was confirmed by ATR-FTIR, H1NMR and DSC analyses. The rheological attributes revealed that the carboxymethylation of TC lowers the viscosity, enhance thermal stability (high activation energy), disentanglement was near to re-entanglement, and weak gelling characteristic. However, the soluble fluconazole loaded gel formulation of CMTC showed diffusion based kinetic model indicating good reservoir for effective application on skin/tissue surfaces.