Development and Characterization of Liposomal Disodium Ascorbyl Phytostanyl Phosphates (FM‐VP4)

Abstract

The specific objectives of this project were (1) to develop liposomal disodium ascorbyl phytostanyl phosphate (FM‐VP4) formulations, (2) to develop a liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) assay for quantification of FM‐VP4 in liposomal formulations and plasma sample, and (3) to characterize liposomal FM‐VP4 formulations by finding optimal drug‐to‐lipid ratios and determining the degradation of FM‐VP4 in liposomes. Section 2 describes an LC/MS/MS assay developed for the identification and quantification of FM‐VP4 in liposomal formulations to provide estimates of drug concentrations and encapsulation efficiency. The extra step of removing plasma proteins prior to LC/MS/MS assay yields an analysis of FM‐VP4 in plasma samples. Section 3 describes experiments designed to find the optimal drug‐to‐lipid ratio for liposomal FM‐VP4 formulations by comparing encapsulation efficiencies and varying the lipid compositions. Additionally, this section details our degradation studies to determine if liposomes have any protective effects on FM‐VP4; these studies tested various lipid compositions at 37°C in rabbit plasma. The mechanism of how FM‐VP4 lowers low‐density lipoprotein (LDL) cholesterol and total cholesterol levels in various animal models is presently unknown. However, before the mechanism of action could be studied, FM‐VP4 first had to be delivered efficiently into plasma or cultured cell. The low systemic bioavailability and cellular uptake of FM‐VP4 further suggested the importance of finding an efficient delivery vehicle for this drug. This project proposed a framework for such delivery and paves the way for further investigation into how FM‐VP4 works in vivo and in vitro.