Development and Evaluation of Modified Dioscorea hispida Starch as a Sustainable Super-Disintegrant for Immediate-Release Tablets

This study developed a sustainable super-disintegrant derived from Dioscorea hispida Dennst. var. hispida starch for use in immediate-release pharmaceutical tablets. Native starch (NS) was extracted and chemically modified via carboxymethylation to obtain carboxymethyl starch (CMS), followed by phosphate cross-linked to yield modified starch (MS). Physicochemical properties demonstrated that MS exhibited superior water uptake, swelling, and viscosity compared to NS and CMS. Scanning Electron Microscopy (SEM) revealed smaller and more uniform granules in MS, confirming enhanced structural modification. Preliminary tablet trials with dicalcium phosphate showed that 4% w/w MS achieved the fastest disintegration (16.5 s). In paracetamol tablets prepared by wet granulation, MS significantly improved hydration and disintegration performance relative to NS and CMS. Although commercial sodium starch glycolate (SSG) provided slightly faster disintegration, dissolution profiles of tablets containing MS and SSG were statistically equivalent (f1 = 7, f2 = 63), confirming comparable efficacy. Porosity analysis using synchrotron radiation X-ray tomography (SR-XTM) indicated that wet-granulated tablets possessed higher intra- and inter-granular porosity than direct compression tablets, facilitating rapid water penetration and disintegration. In contrast, denser direct compression tablets exhibited greater friability and lower mechanical integrity. Modified Dioscorea hispida starch demonstrated excellent disintegration efficiency, eco-friendliness, and local availability, presenting a promising natural alternative to synthetic super-disintegrants in immediate-release tablet formulations.