Fenofibrate Solid Dispersion Processed by Hot-Melt Extrusion: Elevated Bioavailability and Its Cell Transport Mechanism

Fenofibrate (FNB) is an effective drug for the treatment of hypertriglyceridemia, hypercholesterolemia as well as mixed hyperlipidemia. However, due to its poor aqueous solubility, FNB has the problem of poor oral absorption followed by low bioavailability.The aim of this research was to construct FNB amorphous solid dispersion employing PVP VA64 as the carrier by hot-melt extrusion method, in order to improve the oral bioavailability. Additionally, the cell transport experiment was conducted to further investigate the mechanism of promoted osmotic absorption.The physical state of the obtained solid dispersion was characterized using SEM, DSC and XRD. Besides, in vitro Caco-2 cells were used to evaluate the cytotoxicity of the carrier and mimic gastrointestinal drug permeation. At last, in vitro dissolution test and in vivo bioavailability study were also carried out.The prepared FNB solid dispersion was found to be an amorphous state after hot-melt extrusion process. In vitro cytotoxicity test on Caco-2 cells confirmed the excellent biocompatibility of the carrier PVP VA64. Besides, transwell cell transport assay and in vitro dissolution test revealed that FNB released from amorphous solid dispersion was equipped with an improved transmembrane transport and dissolution rate. Moreover, pharmacokinetic study in beagle dogs showed that comparing with commercial micronized product Lipanthyl®, the oral bioavailability of FNB solid dispersion was significantly enhanced (2.45 fold).In conclusion, PVP VA64 can be regarded as a promising polymer to enhance the bioavailability of poorly water-soluble drugs such as FNB processed by hot-melt extrusion. Besides, investigations on the mechanism of the enhanced penetration are expected to lay a foundation on the subsequent development of effective and practical solid dispersion.