Carboxymethyl Starch: A Contemporary Paradigm for Anti Cancer Drug Delivery

Carboxymethyl starch (CMS) represents a significant advancement in addressing the multifaceted challenges of anticancer drug delivery, including poor aqueous solubility, nonspecific biodistribution, and premature drug release. The strategic incorporation of carboxymethyl moiety (-CH₂COOH) onto the starch backbone confers a suite of physicochemical properties that markedly enhance its efficacy as a drug carrier. The carboxymethyl groups, with a pKa of approximately 4.5, exhibit pronounced pH-responsiveness, undergoing a transition from a predominantly deprotonated, hydrophilic state at physiological pH (7.4) to a more protonated form in the acidic tumor microenvironment (pH 6.5-6.8) facilitating targeted drug release at neoplastic site. The mucoadhesive attributes ascribable to carboxyl-mucin interactions, prolong gastrointestinal residence time for oral formulations, optimizing drug absorption. Furthermore, these functional groups serve as reactive sites for subsequent modifications, facilitating the development of multifunctional, targeted drug delivery systems with enhanced biocompatibility and minimized off-target effects. The versatility and biocompatibility of CMS position it as a promising platform for next-generation anticancer therapeutics, offering potential for significant advancements in oncological treatment modalities.