Solvent evaporation, solvent extraction and spray drying for polylactide microsphere preparation

Abstract

Polylactide microspheres containing vitamin D 3 (D 3) as a model drug were prepared by solvent evaporation, solvent extraction and spray drying. In this work, these three different preparation methods were compared and the extent to which each can affect the properties and characteristics of microspheres was identified. The experimental conditions yielding the best results were chosen within each method. Solvent extraction proved to be the better of the two traditional methods. It resulted in particles that were more regular in shape, smaller, with a narrower size distribution and higher porosity. Spray drying yields results equivalent to those of solvent extraction with the advantage of a higher encapsulation efficiency and shorter duration for the process of preparation. Moreover, the dissolution profile of microspheres prepared by spray drying demonstrated that more gradual release of drug was promoted.