Formation of gemfibrozil with narrow particle size distribution via rapid expansion of supercritical solution process (RESS)

Micronized gemfibrozil (GEM) particles were produced by the process of rapid expansion of supercritical solutions (RESS). An experimental design was used to investigate the effects of three process parameters including extraction temperature (25 to 55 °C), extraction pressure (100 to 250 bar) and nozzle diameter (150 to 240 μm) on the particle size distribution (PSD) and morphology of the produced particles. The characterization of the particles was carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements to evaluate the produced particles. The average particle size of the unprocessed material was 30 μm ± (2.5). The average particle size of GEM after processing via the RESS process was between the minimum of 0.8 μm ± (0.03) and the maximum of 2.2 μm ± (0.057) depending upon the process parameters. The results showed that both increasing the temperature from 25 to 55 °C and increasing the nozzle diameter from 0.15 to 0.24 mm caused an increasing effect on the average particle size, whereas increasing the extraction pressure (100–250 bar) led a decrease in the average particle size.