Carboxymethyl Starch as a Pharmaceutical Excipient: A Comprehensive Review of its Synthesis, Properties, and Multifunctional Applications in Drug Delivery

The current review offers a detailed examination of Carboxymethyl Starch (CMS), an important modified polysaccharide in the context of the Pharmaceutical Sciences. We provide information on how this compound is chemically synthesized through carboxymethylation, outlining how reaction conditions will greatly affect the Degree of Substitution (DS) of CMS, which will in turn influence its physical characteristics and functional abilities. Also, various functions of CMS, including its known use as a superdisintegrant (Sodium Starch Glycolate) in the formulation of Immediate Release Solid Dosage Forms and as a binder, thickener, and stabilizer in many types of formulations. A major focus of the review is on the mechanism of action involved in the rapid disintegration of tablets, in particular the combination of swelling and electrostatic repulsion leading to tablet fragmentation. Emphasis have been made for a new approach to utilizing CMS as a 'smart' polymer for innovative Drug Delivery Systems, as it can be utilized based on its intrinsic pH and mucoadhesive properties to allow more effective and targeted drug release. The review compares CMS to other leading excipients, reviews important variables associated with the formulation process and manufacturing processes, and outlines the regulatory and safety profiles of CMS. Current limitations and future scenarios are examined, thus confirming that CMS is an extremely flexible and essential tool in developing Pharmaceutical Products.