Objective To prepare a sustained release tablet formulation from the extract of Dioscorea panthaica Prain.Methods Hydroxypropyl methylcellulose was used as a hydrophilic matrix of the tablet.The formulation of the tablet was optimized by in vitro drug release test.The effects of content and viscosity of hydroxypropyl methylcellulose,the hardness of the tablet,on drug release were discussed.Results Colorimetric assay for diosgenin was developed to determine the in vitro release of the tablet.The RSD was 1.8%...