Encapsulation of BSA using a modified W/O/O emulsion solvent removal method.

A systematic investigation of protein encapsulation in polylactic-co-glycolic-acid (PLGA) was carried out using the formation of a w/o/o emulsion followed by solvent removal. Various factors were studied, including composition of the suspension medium and the relative amounts of aqueous phase containing protein to polymer solution. High yields of microsphere fabrication were achieved by using silicon oil containing methylene chloride as a suspension medium instead of pure silicon oil, with minimal loss of polymer and protein drug (<2%). The amount of aqueous phase influenced the process and successful encapsulation was obtained if the volume ratios of aqueous phase to polymer solution were less than 5% (v/v) at a wide range of polymer concentration (2-15% g ml-1). Protein encapsulation by this w/o/o emulsion and solvent removal method has a high yield of microsphere fabrication and protein encapsulation (98%). In addition, it provides an easy way to control the release rate of protein encapsulated in microspheres by modulating their porosity in fabrication process.