Development of a novel starch-derived porous silica monolith for enhancing the dissolution rate of poorly water soluble drug

Abstract

A novel starch-derived porous silica monolith (PSM) and porous starch foam (PSF) were developed as a carrier in order to improve the dissolution of lovastatin. PSM was prepared by the starch gel template method and PSF was prepared by the solvent exchange method. The morphology and structure of PSM and PSF were characterized by scanning electron microscopy (SEM) and nitrogen adsorption/desorption analysis. Lovastatin was loaded into PSM and PSF by immersion/solvent evaporation. Nano-pore spatial confinement effect on the drug dissolution was systematically studied by SEM, Fourier transform infrared spectroscopy (FTIR), thermogravametric analysis (TGA), x-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and in-vitro drug dissolution studies. Lovastatin adsorbed in PSM was amorphous and lovastatin absorbed on PSF was partially present as microcrystal in the pores of PSF and partially in crystalline form distributed on the surface of PSF. PSM and PSF allowed immediate release of lovastatin and enhanced the dissolution rate. These results provide important information about the mechanism of drug adsorption and release. Accordingly, PSM and PSF have a promising future as a vehicle for the oral delivery of poorly water soluble drugs. Moreover, the effect of PSM is better than that of PSF.