In Vitro Release and Bioavailability of Silybin from Micelle-Templated Porous Calcium Phosphate Microparticles

Developing a promising carrier for the delivery of poorly water-soluble drugs, such as silybin, to improve oral absorption has become a very worthy of consideration. The goal of this study was to prepare a novel porous calcium phosphate microparticle using povidone-mixed micelles as template while evaluating its in vitro and in vivo properties with silybin as a model drug. The particle characterization, in vitro drug release behavior, and pharmacokinetic parameters of the prepared silybin-loaded calcium phosphate microparticle were investigated. The mean particle size was found to be 3.54 +/- 0.32 mu m with a rough surface porous structure. Additionally, the silybin-loaded calcium phosphate microparticle compared with the free silybin showed a prolonged 72-h release in vitro and a higher C-max (418.5 +/- 23.7 ng mL(-1)) with 167.5% oral relative bioavailability. A level A in vitro-in vivo correlation ( IVIVC), established for the first time, demonstrated an excellent IVIVC of the formulated silybin in oral administration. In conclusion, this povidone-mixed micelle-based microparticle was successfully prepared to enhance the oral bioavailability of silybin. Therefore, application of this novel porous calcium phosphate microparticle holds a significant potential for the development of poorly water-soluble drugs.