Research progresses on carboxymethyl xanthan gum: Review of synthesis, physicochemical properties, rheological characterization and applications in drug delivery

Xanthan gum is a nonionic polysaccharide widely explored in biomedical, nutraceutical, and pharmaceutical fields. XG suffers from several drawbacks like poor dissolution, lower bioavailability and an inability to form hydrogels. The carboxymethyl derivative of XG, CMX, has better solubility, dissolution, and bioavailability characteristics. Moreover, due to its anionic character, it forms water insoluble hydrogels upon crosslinking with metal cations. CMX hydrogels are used to prepare matrix tablets, microparticles, beads, and films. CMX hydrogels has been used in drug delivery and tissue engineering fields. CMX hydrogels are used for sustained gastrointestinal, colon targeted, and transdermal delivery of drugs. CMX nanoparticles have been used for targeted delivery of anticancer drugs to tumor cells. CMX hydrogels have already made significant strides in drug delivery and tissue engineering fields. Further understanding of the physicochemical properties and rheological characteristics of CMX would enable researchers to explore newer applications of CMX. This review article thus aims to discuss the synthesis, physicochemical properties, and rheological characteristics of CMX. The article also gives critical insights on the versatility of CMX as a drug delivery carrier and presents prospective trends on applications of CMX.