Advancement in Sodium Alginate-Based Drug Delivery Systems: Applications and Future Prospects.

For over five decades, sodium alginate (SA) has been widely employed in pharmaceutical formulations due to its environmentally friendly, biodegradable, and biocompatible nature. Primarily sourced from brown seaweed, this natural polymer plays a crucial role in enhancing drug delivery control. It serves as a versatile excipient in numerous dosage forms such as capsules, tablets, liposomes, and microspheres. SA ionotropic gelation with calcium ions allows drug and enzyme encapsulation for controlled release. Structurally, SA consists of α-L-guluronic acid and β-D-mannuronic acid monomers linked via glycosidic bonds, enabling the formation of strong, porous hydrogels capable of carrying bioactive substances. These hydrogels have been extensively utilized in ocular and oral drug delivery systems for prolonged therapeutic effect. This review highlights the structural and physicochemical characteristics of SA, its pharmaceutical and biomedical applications, food industry relevance, and recent innovations, while also discussing its potential as a multifunctional material for future drug delivery systems.