PMMA+Budesonide Particles Produced with the Supercritical Antisolvent Precipitation Process

   The Supercritical Antisolvent (SAS) Precipitation Process can be used to create microparticles of various materials. The ultimate goal of this research is to be able to design drug-polymer particles of specific size, morphology, and drug-loading by controlling underlying mechanisms of the SAS precipitation process. The relationships between process conditions and both spray characteristics and particle characteristics are discussed.

   This study uses the SAS precipitation process to create micron-sized poly(methyl methacrylate)+budesonide particles at various operating conditions. In this study, 1 wt% PMMA+budesonide (90+10) in acetone solution is sprayed into supercritical carbon dioxide. The spray is characterized using a high magnification visualization technique. When the pressure of the carbon dioxide is increased, the average droplet size of the spray appears to increase, as visualized 3mm below the spray nozzle. When pressure and temperature are changed but density is kept constant, there appears to be no change in average droplet size. Based on an analysis of the scanning electron micrographs of the particles collected, the results of this study also indicate that changing the operating conditions have no effect on the particle size and size distribution. The protocol for determining the concentration of the polymer-drug particles created is also outlined.