Sulfate alginate microparticles for controlled release of water-soluble drugs

Sulfated derivatives of alginate represent a promising class of carbohydrate-based biopolymers with tunable physicochemical and biological properties. In this study, sodium alginate (SA) and sodium sulfate alginate (SSA) were combined at different ratios (SA90:SSA10, SA70:SSA30, and SA50:SSA50) to fabricate mafenide acetate–loaded microparticles via a water-in-oil emulsion crosslinking technique. The influence of sulfate substitution on microparticle morphology, drug release kinetics, antibacterial behavior, and cytocompatibility was systematically investigated. The optimized SA50:SSA50 formulation exhibited uniform spherical morphology, enhanced surface roughness, and a markedly controlled drug release profile, releasing approximately 65% of mafenide acetate over 28 days. Fourier-transform infrared spectroscopy confirmed the presence of sulfate–alginate interactions and successful drug incorporation, while AFM revealed nanoscale surface heterogeneity favoring drug adsorption. Furthermore, SA50:SSA50 microparticles demonstrated significant antibacterial activity against E. coli and S. aureus and excellent fibroblast compatibility. These findings highlight the crucial role of alginate sulfation in tailoring drug diffusion and antibacterial performance, providing a versatile carbohydrate-based platform for controlled drug delivery and wound healing applications.