Bleich J, Müller B W
Department of Pharmaceutics and Biopharmaceutics, Christian-Albrechts-University, Kiel, Germany.
J Microencapsul. 1996 Mar-Apr;13(2):131-9. doi: 10.3109/02652049609052902.
The aerosol solvent extraction system (ASES) uses a supercritical gas as non-solvent for an organic solution of drug and polymer in order to form microparticles by a flocculation process. Due to the miscibility of organic solvent and supercritical gas phase, microparticles with residual organic solvents below 30 ppm are formed. This principle was tested to encapsulate model drugs such as hyoscine butylbromide, indomethacin, piroxicam and thymopentin. As a carrier, the polymer poly-L-lactide was used. The resulting microparticles were investigated with regard to particle formation, morphology, particle size, size distribution, and drug loading. With decreasing, polarity of the incorporated drug, an increasing extraction occurs which lowers the drug loading of the microparticles. The extraction capacity of the gas phase depends on temperature and pressure which determines density and polarity of the gas. The obtained results show that the production conditions have to be optimized for each drug/polymer combination. Totally non-polar drugs are completely extracted together with the organic solvent, however, polar drugs, and here especially peptides and proteins, are easy to incorporate with the ASES process.
气溶胶溶剂萃取系统（ASES）使用超临界气体作为药物和聚合物有机溶液的非溶剂，通过絮凝过程形成微粒。由于有机溶剂与超临界气相的混溶性，形成了残留有机溶剂低于30 ppm的微粒。该原理已用于包封诸如丁溴东莨菪碱、吲哚美辛、吡罗昔康和胸腺五肽等模型药物。使用聚合物聚-L-丙交酯作为载体。对所得微粒的颗粒形成、形态、粒径、粒径分布和载药量进行了研究。随着掺入药物极性的降低，萃取量增加，这降低了微粒的载药量。气相的萃取能力取决于温度和压力，而温度和压力决定了气体的密度和极性。所得结果表明，对于每种药物/聚合物组合，都必须优化生产条件。完全非极性的药物会与有机溶剂一起被完全萃取出来，然而，极性药物，尤其是肽和蛋白质，很容易通过ASES过程被包封。
