Effects of processing parameters on the properties of amphiphilic block copolymer micelles prepared by supercritical carbon dioxide evaporation method

The operation parameters for the supercritical carbon dioxide (ScCO₂ ) evaporation method greatly affect the properties of the prepared drug-loaded micelles. In this study, the effects of those key parameters on the drug-loading content (LC) and drug entrapment efficiency (EE) are discussed. It is observed that EE and LC of the micelles are slightly increased with the enhancing temperature and the copolymer molecular ratio of hydrophilic/hydrophobic segment, while decreased with the enhancing ScCO₂  evaporation rate. The pressure and volume ratio of ScCO₂  to H₂ O are observed the optimum condition. In addition, the verification experiment is carried out under the obtained optimizing parameters. The prepared micelles exhibit relatively regular spherical shape and narrow size distribution with the EE and LC value of 70.7% and 14.1%, respectively.