Production of PLGA micro- and nanocomposites by supercritical fluid extraction of emulsions: I. Encapsulation of lysozyme

Micro- and nanoparticles of bio-compatible and bio-degradable polymers such as poly-lactic-co-glycolic acid (PLGA) are widely used as delivery devices for the administration of sensitive biopharmaceuticals such as proteins, peptides and genes. The purpose of this study is the investigation of supercritical fluid extraction of emulsions (SFEE) as a novel process for the production of such particles. By variation of PLGA concentration and stirring rate during emulsion preparation, particles of pure PLGA with average sizes ranging between 100 nm and a few mu m with very narrow size distributions have been produced in controlled and reproducible manner. Moreover, lysozyme has been used for the formation of composite particles with PLGA. Three different encapsulation methods have been investigated and evaluated by determining the corresponding encapsulation efficiencies. With the method of in situ suspension emulsions, an encapsulation efficiency of up to 48.5% has been achieved. The current study highlights the potential of SFEE as an attractive and scalable process for the manufacturing of drug-PLGA composite particles for pharmaceutical applications. (C) 2009 Elsevier B.V. All rights reserved.