Utilizing Response Surface Methodology to Optimize and Characterize Extruded Partially Pregelatinized Cassava Starch for Tablet Binding Applications

Cassava starch is an abundant and underutilized natural resource with significant potential for pharmaceutical applications, yet its native form often exhibits suboptimal functionality as a binder. Physical modification methods, such as extrusion, offer a promising approach to enhance starch properties in an energy-efficient and environmentally friendly manner. This research focused on optimizing the extrusion process for producing partially pregelatinized cassava starch (PPCS) and assessing its potential application as a binder in tablet formulation. Optimization was conducted using Response Surface Methodology (RSM) with moisture content (30–40%) and extrusion temperature (30–45°C) as independent variables. The optimal condition—30% moisture and 45°C extrusion temperature—yielded a degree of gelatinization (DG) of 45.67% and solubility of 52.08%. Morphological analysis showed polygonal granules with retained birefringence and no granule damage, while X-ray diffraction revealed reduced relative crystallinity compared to native starch. The optimized PPCS exhibited superior flowability (13.81 g/s) and compressibility index (21.26%), outperforming native starch and Starch 1500. Tablet formulations using 45–50% PPCS binder showed promising physicomechanical properties, with tensile strength ranging from 1.31 to 1.76 MPa, friability below 3%, and rapid disintegration time under 2 minutes. Despite slightly lower tablet hardness (4.21–4.72 kg) compared to the benchmark, all values remained within acceptable specifications. These findings indicate that extruded PPCS is a cost-effective, energy-efficient, and high-performance binder for pharmaceutical tablet formulations, particularly those containing brittle medicinal powders. The extrusion method presents an effective physical modification process, enhancing cassava starch's functionality while preserving desirable granule features.