separation of ibuprofen racemate by supercritical fluid chromatography

초록

The chiral compound, enantiomer, has the same chemical structure and physical properties without optical property. It showed different activity in human body. generally, one of the enantiomer pair has pharmaceutical activity, while the other has side effect such as poison. Therefore, the interest of enantiomer separation with the high purity was gradually increased in recent years. The chromatographic separation using chiral stationary phases (CSPs) have been widely applied. In supercritical fluid chromatography(SFC), the lower viscosity of the mobile phase and high diffusivities of the solutes more often shows better resolution and shorter run times than LC (Liquid Chromatography) methods. The lower viscosity provides the ability to use high flow-rate in SFC. The use of pure supercritical fluid (for example, carbon dioxide) as the mobile phase enables an easy product recovery by depressurizing the supercritical fluid without any additional rectification step. Another unique feature of the SFC process is the opportunity to change the solvent strength of the mobile phase by pressure and temperature, respectively, in order to optimize the separation condition. The aim of this work was to determine the optimum condition to separate chiral compounds and compare the experimental scheme with LC method. The standard chemical used was ibuprofen[2-(4-isobutylphenyl) propionic acid]. It was a non-steroidal anti-inflammatory drug (NSAID) belonging to the group of propionic acid derivatives. S(+)-enantiomer has pharmacological activity. The effect of percent of organic modifier (IPA), temperature and pressure of supercritical fluid on resolution of the racemate were experimentally investigated to adjust the retention times. Compared to HPLC method, the allowable amount of injection for a complete separation was higher in SFC, because the shape of peak was symmetric at a larger loading of sample.