Physicochemical properties of tablet dosage form based on pre-gelatinized- and phosphorylated-modified starches from white-water yam (Dioscorea alata L.)

Abstract

Background White-water yam (Dioscorea alata L.) is one of the potential sources of starch; however, it is not yet available for commercial purposes. Besides, native white-water yam starch (WS) presents limited functionality due to poor flowability, mechanical properties and instability at high temperature and acidic conditions. Therefore, this study aims to modify the starch to improve its characteristics and make it useful as an excipient for the preparation of the tablets. Materials and methods The modification of WS was achieved by physical and chemical treatments, specifically pre-gelatinization and phosphorylation, respectively. Pre-gelatinization WS involves heating, meanwhile phosphorylation WS is obtained by treating WS with sodium tripolyphosphate. Results The results showed that the powder of the modified WS has good characteristics which improved the flowability of the powder mixture as a granule based on density, porosity, compressibility index and swelling power determination. The WS granules were found to display the oval or irregular (polygonal) shape with the amylose content 11.92±0.61% for unmodified WS, 10.41±0.90% for pre-gelatinized WS and 12.61±1.75% for phosphorylated WS. Furthermore, the granule was formulated as an excipient in tablet preparations, and the formulas were compressed after wet granulation. The mechanical properties of the tablets were assessed using uniformity of mass and size, hardness, friability and disintegration time. WS modification affects the hardness of tablets when used as a binder. Phosphorylated WS is recommended to be used as a binder in wet granulation formulations because it produces tablets with a longer disintegration time, which means better binding ability. However, the utilization of modified WS with both pre-gelatinization and phosphorylation leads to tablets with low brittleness compared to others with unmodified binder with the disintegration time still met the requirement of fast disintegrating tablet (<15 minutes). Conclusion All the physical properties studied indicated that the modified WS is a promising pharmaceutical excipient in tablets.