Potential use of albumin microspheres as a drug delivery system. I. Preparation and in vitro release of steroids

Abstract

Albumin microspheres were prepared by two different stabilization processes: chemical denaturation and heat denaturation. The extent of stabilization was characterized by the solubility and the swelling properties of the microspheres. In vitro drug (prednisolone) release rates were determined for the different microsphere preparations and the results were correlated to the stability of the microspheres. Heat denaturation had a significant effect on the in vitro release rates; the more denatured the albumin, the slower the drug release rate. Chemical denaturation, using glutaraldehyde, did not have a marked effect on drug release from the microspheres. Two of the major limitations of albumin microsphere systems i.e. poor drug entrapment and premature release (“burst effect”) have been overcome using prednisolone loaded heat denatured microspheres.