Retention reproducibility of thiazide diuretics and related drugs in reversed-phase high-performance liquid...

A method has been developed for the separation of thiazide diuretics and a number of related drugs by high-performance liquid chromatography on an ODS-Hypersil column with acetonitrile-1% aqueous acetic acid as the eluent. The effects caused by changes in the separation conditions on the reproducibility and robustness of alternative methods for recording retentions (including capacity factors, retention indices based on the alkyl aryl ketone scale, and relative capacity factors compared to a thiazide standard) have been examined. The results confirm that good interlaboratory reproducibility will only be achieved when operators control the temperature of the column and use the same brand of column packing material. The retentions should be recorded using a relative method, as these were found to be virtually independent of minor variations in the eluent composition.