Preparation And The Physical-chemistry Properties Of Silybin Liposme

Liposome is a spherical vesicle, which is composed of phospholipid, cholesterol and other substances in water. Liposome is a good drug carrier with good biocompatibility and safety. There are many advantages compared with other drug delivery systems. In this paper, silybin is chosen as a drug model. The technique of the preparation of liposome, the physical -chemistry properties of liposome, and the solubility of silybin in some organic solvents were studied. This study is aimed to provide basic reference data for the preparation and application of silybin liposome. Following cotents are included in this paper.1. The silybin liposome was prepared by a thin film ultrasonic dispersion method. The liposome and drug was separated by a dialysis method. The solubility of silybin was measured by the UV-visible measurement. The content of silybin in liposome and the entrapment efficiency were determinated from its solubility data. Entrapment efficiency was used to evaluate the efficience of liposome. In experiment, three factors infect the entrapment efficiency and particle size distribution: the ratio of phospholipid to cholesterol, the amount of silybin in liposome, hydration media types. A four-level three - factors orthogonal experiment was designed to optimize the prescription. The optimum prescription is that the ratio of EPC: cholesterol = 100:50, silybin was 10mg, hydration medium was 0.01MPBS (pH = 6.86). The entrapment efficiency of 86.57% is found for the optimum prescription.2. The physical-chemistry properties of silybin liposome were studied by FT-IR spectroscopy, DSC, TEM and the drug release experiments. The results of FT-IR showed that silybin is simply enclosed in phospholipid liposome. DSC experiment shows that cholesterol could inhibit EPC from phase transition. TEM shows that silybin liposome is a spherical vesicle. The particle size was distributed from 64.29 to 250.00 nm, the average size was 123.48 nm. Drug release experiment was analysed by some kinetic equations. For example the Zero-order equation, the first-order equation, the Higuchi equation, the Niebergull square root equation, the Hixcon-crowell cube root equation and the Weibull equation. The results of data fit indicate that the first-order equation agrees with experimental best.3. The solubility of silybin in several organic solvents such as ethanol, Acetone, Ethyl Acetate and dimethylformamide was measured by the solid-liquid equilibrium method. Ideal solution model, empirical model, Apelblat model andλh model were used to correlate the experimental data.The empirical model and Apelblat model correlate the solubility data better.