Fabrication of Pharmaceutical Nano Particles Through RESS Process; Influence of Temperature, Pressure and Co-solvent

Reducing the size of pharmaceutical particles enhances their solubility and bioavailability and therefore inhibits their side effects. An advantageous method to produce fine particles is using supercritical fluids technologies among which the rapid expansion of supercritical solutions (RESS) is of a significant importance in producing pure pharmaceuticals since no organic solvent is used. In this work, submicron particles of megestrol acetate (MA) were precipitated by RESS method, using CO2 as supercritical fluid in the presence of menthol as solid co-solvent. The effects of extraction temperature, extraction pressure and weight percent of menthol on the mean particle size of precipitated particles was investigated. The experiments were carried out at three temperature levels from 40 to 60ºC, three pressure levels from 15 to 25 MPa, and with 2 to 6 wt% of co-solvent. Megestrol acetate particles were formed with mean particle sizes between 102.8 to 516.3 nm. Statistical analysis showed that pressure had the most considerable effect on mwan particle size. Increasing the temperature and pressure, and decreasing the amount of solid cosolvent resulted in a product with smaller mean particle size.