Preparation and characterization of liposomes-in-alginate (LIA) for protein delivery system

This paper describes the preparation and characterization of a novel drug delivery system for protein, liposomes-in-alginate (LIA) of biodegradable polymers, which is conceived from a combination of the polymer and the lipid-based delivery systems. LIA were prepared by first entrapping bovine serum albumin (BSA), a model protein within multivesicular liposomes (MVLs) by double emulsification process, which are then encapsulated within alginate hydrogel microcapsule, with untrapped BSA which are added during preparation of MVLs. Factors impacting encapsulation efficiency of MVLs are investigated and release of protein from the microcapsules in vitro is studied. At the same time, characterization of MVLs, microcapsules encapsulated protein formulation and integrality analyse of BSA in microcapsules are also studied, with the aim of improving the entrapment efficiency and prolonging release time. It is found that encapsulation efficiency and size of MVLs are affected by the composition and fabrication parameters of LIA. The data also show LIA have high encapsulation efficiency (up to 95%), little chemical change in drug caused by the formulation process, narrow particle size distribution and spherical particle morphology. Drug release assays conducted in vitro indicates that these formulations provide sustained release of encapsulated drug over a period, about 2 weeks. (c) 2005 Elsevier B.V. All rights reserved.