Material properties, compressibility, and tabletability of planetary ball-milled glutinous rice starch and its application as a mucoadhesive disc for buccal delivery: Impact of milling duration

This study examined the material properties, compressibility, and tabletability characteristics of glutinous rice starch modified by planetary ball milling as a function of milling duration as well as the utilization of ball-milled glutinous rice starch (BMGS) as a mucoadhesive disc carrier for buccal delivery. Planetary ball milling caused crystallinity loss, which was accompanied by enhanced starch functionality. Prolonged milling significantly altered particle size, morphology, powder density, and compressibility index. The compressibility assessed using the Heckel and Kawakita models suggests that plastic deformation is a significant process during compression. The compressibility of the BMGS decreased with the milling time. Tabletability, assessed via tablet tensile strength (TS), was enhanced with BMGS compared with native starch. 60-min-BMGS displayed superior TS compared to the 30-min-BMGS. Active pharmaceutical ingredients (API) lowered the TS of starch tablets. 60-min-BMGS exhibited the greatest sensitivity to API loading. BMGS demonstrated efficacy as a mucoadhesive disc matrix for the delivery of both hydrophilic and hydrophobic APIs, displaying the capacity to modulate API release for up to 6 h. This investigation provides essential insights into ball milling as an approach for enhancing the material and tabletability of starch to produce an alternative pharmaceutical excipient.