Chromatographic approaches to the quality control of chiral propionate anti-inflammatory drugs and herbicides.

The chiral analysis of a range of propionate anti-inflammatory drugs and herbicides was accomplished by gas chromatographic separation of their R-alpha-phenylethylamide diastereomeric derivatives. Using a packed column (3% OV-l on Chromosorb G) good separations were obtained but analysis times were rather long. Examination of the same crystalline derivatives using a capillary column (bonded methylsilicone) resulted in good separations together with much reduced total analysis times. The technique was validated through the analysis of several derivatives prepared on a micro scale and examined directly by gas chromatography without any crystallisation step. Racemic materials all gave virtually 50:50 response ratios while the analysis of optically pure samples produced no evidence of significant racemization. Derivatives of phenoxyacetic acid and myristic acid were also prepared and chromatographed as potential internal standards.