A simultaneous packed column supercritical fluid chromatographic method for ibuprofen, chlorzoxazone and acetaminophen in bulk and dosage forms.

A reproducible and efficient method for the separation and estimation of ibuprofen, chlorzoxazone and acetaminophen has been developed using packed column supercritical fluid chromatography (SFC). The separations were performed on an ODS-RP JASCO column employing methanol modified supercritical fluid CO(2) as the mobile phase. The densities and polarities of the mobile phase were optimised from the effects of pressure, temperature and modifier concentration on retention times. In addition a flow programming of the mobile phase helped to obtain better resolution and a faster elution for acetaminophen. The analytes were detected using a uv detector at 254 nm. The study includes a successful attempt at quantitation of the 3 drugs. Chromatographic figures of merit, linear dynamic range, limit of quantitation (LOQ), precision and accuracy etc. were determined to assess the viability of the method. The method has been extended to commercial dosage forms containing all 3 drugs.