Influence of post-emulsification drying processes on the microencapsulation of Human Serum Albumin - Spray Drying

Influence of post-emulsification drying processes on the microencapsulation of Human Serum Albumin
Received 8 June 2005; revised 8 September 2005; accepted 24 September 2005. Available online 4 November 2005.
Majella E. Lanea, , , Fiona S. Brennanb and Owen I. Corriganb
International Journal of Pharmaceutics
Volume 307, Issue 1 , 3 January 2006
ScienceDirect
Copyright ? 2005 Elsevier B.V. All rights reserved.
aThe School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK
bSchool of Pharmacy, Trinity College, Dublin 2, Ireland
Abstract
In the present work, methods used to microencapsulate Human Serum Albumin (HSA) in a biodegradable polymer were compared for their effects on the physicochemical characteristics of HSA-loaded microparticles and on the release and integrity of encapsulated HSA. The polymer used was poly(d,l-lactide-co-glycolide) (75:25) (PLGA) (Boehringer Ingelheim, Resomer RG 752, MW 20,900). Microparticles were formulated by (i) w/o/w emulsification and freeze-drying (EFD) or (ii) w/o/w emulsification and spray-drying (ESD). Particle morphology and size were evaluated by scanning electron microscopy and by laser diffraction analysis. Loading, encapsulation efficiency and protein release were determined using a commercial protein assay kit. Protein integrity was evaluated by sodium dodecyl sulphate?polyacrylamide gel electrophoresis (SDS?PAGE) analysis. Particles produced by emulsification/spray-drying exhibited greater diversity in shape than those produced by emulsification/freeze-drying. Additionally, protein loading values were significantly higher for particles produced by emulsification/spray-drying rather than particles produced by emulsification/freeze-drying. The structural integrity of encapsulated protein was confirmed for particles produced by both processes. The fraction of HSA released was similar for both formulations. The emulsification/spray-drying technique described appears to be a rapid and efficient method for the preparation of PLGA microparticles loaded with a model protein.
Keywords: PLGA; Human Serum Albumin; Water-in-oil-in-water emulsion; Freeze-drying; Spray-drying
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