ROLE OF NATURAL POLYMERS IN DESIGNING CONTROLLED-RELEASE MATRIX TABLETS: A REVIEW

Sustained-release (SR) oral formulations have emerged as a crucial strategy to maintain therapeutic drug levels over extended periods, reduce dosing frequency, minimize side effects, and improve patient adherence. Among SR systems, matrix tablets are widely used due to their simplicity, cost-effectiveness, and predictable performance. Natural polymers, including xanthan gum, guar gum, chitosan, sodium alginate, and starch derivatives, have gained significant attention as matrix formers owing to their biocompatibility, biodegradability, availability, and regulatory acceptance. These polymers modulate drug release through swelling, erosion, and diffusion mechanisms, allowing for tailored release profiles suitable for drugs with short half-lives, pH-dependent solubility, or narrow absorption windows. This review comprehensively discusses the selection of drugs and natural polymers, formulation considerations, choice of excipients, methods of tablet preparation, and characterization of SR tablets. Advantages and limitations of using natural polymers are also highlighted, emphasizing their potential to provide safe, effective, and environmentally sustainable controlled-release drug delivery systems. Insights into polymer combinations, release kinetics, and in-vitro evaluation are provided to guide future research and formulation optimization. Keywords: Sustained-release, Natural polymers, Matrix tablets, Drug delivery, Controlled release, Xanthan gum, Guar gum, Chitosan, Sodium alginate, Formulation optimization