Isolation and effect of physical modification on the release characteristics Euryale ferox Salisb polysaccharide

This study investigates the potential of native and physically modified Euryale ferox Salisb. (makhana) starch as excipients for colon-targeted drug delivery systems. Physical modifications, including pregelatinization, retrogradation, ultrasonication, autoclave heating, and osmotic pressure treatment, were applied to enhance delayed-release characteristics. Functional analysis revealed improvements in swelling, solubility, and water-holding capacity, attributed to increased amylose content and structural reorganization. FTIR analysis showed significant molecular changes, with prominent peaks at ∼3320 cm^-1 (OH stretching) and ∼ 1742 cm^-1 (CO stretching) in retrograded starch (RMS), reflecting enhanced hydrogen bonding and crystallinity. XRD analysis further confirmed these changes, with characteristic peaks of native starch at ∼13°, ∼17°, and ∼ 22° reduced or shifted, indicating the formation of A-type and B-type crystalline structures in modified starches. The in vitro dissolution studies conducted in simulated gastric (pH 1.2) and intestinal (pH 6.8) media demonstrated the gastroprotective properties of native and modified starch-based tablets, with <25 % drug release at pH 1.2. At pH 6.8, retrograded starch (RMS) and pregelatinized starch (PS-60) exhibited sustained-release profiles, achieving approximately 18 % and 22 % drug release at 2 h and 55 % and 60 % at 6 h, respectively, compared to the rapid release of native starch (95 % at 6 h). Drug release kinetics analysis revealed that the Korsmeyer-Peppas model best described the release profiles of RMS and PS-60 compared to other formulations, indicating a combination of diffusion and erosion mechanisms. These findings establish modified makhana starch as a sustainable, plant-based alternative to conventional excipients, offering enhanced functionality and delayed-release properties for colon-specific drug delivery in treating inflammatory bowel diseases.