PERFORMANCE OF MICELLAR MOBILE PHASES IN REVERSED-PHASE CHROMATOGRAPHY FOR THE ANALYSIS OF PHARMACEUTICALS CONTAINING BETA-BLOCKERS AND OTHER ANTIHYPERTENSIVE DRUGS

A rapid and simple reversed-phase micellar liquid chromatographic proc edure for the simultaneous determination of the beta-blockers atenolol , metoprolol and oxprenolol, the diuretics amiloride, bendroflumethiaz ide, chlorthalidone and hydrochlorothiazide and the vasodilator hydral azine in pharmaceuticals, is proposed, An interpretive optimization pr ocedure, which uses the chromatographic data for only five mobile phas es, was applied to select a suitable micellar mobile phase. A comparat ive study was also made of the performance of micellar and aqueous-org anic mobile phases in the analysis of pharmaceuticals that combine bet a-blockers and diuretics, The determination of all the drugs could be made with a micellar mobile phase of 0.15 mol l(-1) sodium dodecyl sul fate and 7% propanol in 0.01 mol l(-1) phosphate buffer at pH 3, with retention times below 20 min, whereas two different aqueous-organic mo bile phases mere needed to make the same analyses.