High-performance liquid chromatographic method for determining the enantiomeric purity of a benzindene prostaglandin by a diastereomeric separation.
An isocratic high-performance liquid chromatographic (HPLC) method was developed to determine the enantiomeric purity of a benzindene prostaglandin (U-62,840) which is currently being evaluated for pharmaceutical applications. The enantiomers were converted to diastereomeric amide derivatives using optically pure S-(--)-1-phenylethylamine (greater than 99.9%). Separation of the diastereomers was demonstrated on achiral silica-based stationary phases using a hexane-dioxane-water mobile phase and UV detection at 214 nm. Due to the use of an optical derivatizing agent, method validation addressed the issues of optical purity of the reagent and comparative rates of reaction of each enantiomer. Analytical data is reported that demonstrates quantitative derivation, linearity, accuracy, precision, and ruggedness of the optimized assay conditions. Limit of quantitation for the enantiomeric impurity was determined to be 1.1% (signal-to-noise ratio 13). A brief description of the results of a parallel study of an enantiomeric separation using various chiral HPLC columns is included.