Silymarin Spray-Dried Proliposomes: Preparation, Characterization and Cytotoxic Evaluation

Abstract

Background: Most liposomes problems are due to stability and consistency. Proliposomes is one of the solutions to overcome the disadvantage of liposomes. They are available in dry powder form, it is easy to distribute, transfer, measure and store. Objective: The aim of the present study was to find a novel method of preparing Silymarin proliposomes and study the effect of cholesterol concentrations and surfactant types on the physicochemical properties of silymarin proliposomes and its in-vitro release. Methods: Silymarin proliposomes were prepared by combining two simple methods ethanol injection method for liposomes preparation followed by the spray drying method to get a dry powder. The physicochemical properties including particle size, TEM, SEM, FTIR, encapsulation efficiency and dissolution studies were studied. Results: The particle size of silymarin liposomes were below 552.36 ± 17.63 nm but after reconstitution of silymarin proliposomes, the particle size was in the micro range due to the influence of the spray drying process. Cholesterol concentration was ranged from 50 to 150 mg per formula. Increasing Cholesterol concentration caused a significant increase in liposomes particle size and reduction in encapsulation efficiency. Three non-ionic surfactants were used to prepare silymarin proliposomes Tween 80, Cremophor RH 40 and Poloxamer 407. Formula F1 prepared with Phosal® 53 MCT (300 mg), Tween 80 (50 mg), cholesterol (50 mg) and Silymarin (140 mg) showed the smallest particle size (2066 ± 164.87 nm) upon reconstitution in water, highest encapsulation efficiency (89.51 ± 0.43%), and fastest in vitro release compared to other formulas. Cytotoxicity of Silymarin, formula F1 and formula F1/blank was assessed using an MTT assay on MCF-7, HepG2 and HBF-4 cells. The cytotoxic effect of silymarin was enhanced by loading it on proliposomes. Conclusion: Silymarin was successfully formulated into proliposomes combining ethanol injection and spray drying methods. The cytotoxicity of silymarin was improved when loaded on proliposomes owing to the formula.