Generation of microparticles using CO₂ and CO₂‐philic antisolvents

Abstract

Abstract Precipitation using a compressed antisolvent (PCA) is a demonstrated technology for generation of monodisperse ultrafine particles. Microparticle precipitation using CO 2 ‐philic antisolvents was studied with the ultimate goal of developing fundamental approaches to tailor microparticle generation. The ability to micronize small solutes and polymeric systems using CO 2 ‐philic liquid antisolvents is compared to precipitation with compressed CO 2 and traditional antisolvents. Analogies are made between PCA and CO 2 ‐philic antisolvent precipitation based on thermodynamic driving forces and the dynamics of the spray process. Analysis of the interfacial gradient energies of the miscible solvent–antisolvent systems indicates that the spray process is dominated by turbulent mixing and not atomization. The similar microparticle morphologies of amorphous and semicrystalline poly(lactic acid) (PLA) obtained using liquid CO 2 ‐philic antisolvents and compressed CO 2 suggest that a similar demixing mechanism dominates microparticle formation at these operating conditions.