Preparation of PLA-PEG nanoparticles by the solution enhanced dispersion with enhanced mass transfer using ultrasound in supercritical CO2

A modified supercritical antisolvent technique (solution enhanced dispersion with enhanced mass transfer using ultrasound in supercritical CO2, SEDS-EM) has been applied in preparation of PEG loaded PLA nanoparticles. The hydrophilicity of polylactic acid (PLA) nanoparticles has been increased by adding polyethylene glycol (PEG) in order to improve PLA as a controlled release drug system. Uniform distribution of solution tiny droplets by the SEDS-EM method in supercritical CO2 prevents particle agglomeration as well as intensifies the effect of mass transfer. The effects of PEG amount in the PLA/PEG polymer mixture and ultrasonic system on the formation of PLA-PEG nanoparticles have been studied. Operational parameters, such as temperature, pressure, ultrasound power supply and solution flow rate have been also investigated in the current paper. The morphology of PLA-PEG nanoparticles changed from hollow combined structure to nearly spherical form by decreasing the amount of PEG in the PLA/PEG polymer mixture. In addition, particle size reduction has been achieved by decreasing temperature, solution flow rate as well as by increasing pressure and providing ultrasound treatment.

Graphical abstractThe solution can be generated into extremely small droplets during SEDS-EM, which induces the enhanced mass transfer in the supercritical CO2 and the prevention of agglomeration of particles.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A novel method, solution enhanced dispersion in supercritical CO2 with enhanced mass transfer (SEDS-EM), is established to prepare PLA-PEG nanoparticles. ► In this new technique, the solution can be generated into very small droplets, which induces the enhanced mass transfer between supercritical CO2 and solvent. ► Compared with SEDS techniques, SEDS-EM can provide smaller and more uniform particles.