Development and validation of a reversed-phase ultra-performance liquid chromatographic method for the simultaneous determination of six drugs used for combined hypertension therapy.

A simple, rapid, and reliable ultra-performance LC assay method has been developed for the simultaneous estimation of orally administered hypertension drugs (atenolol, hydrochlorothiazide, amlodipine besylate, indapamide, nifedipine, and lercanidipine hydrochloride), any of which may be administered with atenolol in combined hypertension therapy. Chromatography was carried out at 25 degrees C on a 2.1 x 50 mm id, 1.7 microm particle size Acquity BEH C18 column with the isocratic mobile phase 0.01 M, 4.0 pH aqueous phosphate buffer-acetonitrile (50 + 50, v/v) at a flow rate of 0.35 mL/min. All drugs were separated in less than 4 min with good resolution and minimal tailing, without interference by excipients. The method was validated according to International Conference on Harmonization guidelines, and the acceptance criteria for accuracy, precision, linearity, specificity, and system suitability were met in all cases. The column effluent was monitored at 230 nm. The detector response was linear in the range of 1-20 microg/mL of these drugs. LOD obtained was 0.04 microg/mL for atenolol, 0.02 microg/mL for hydrochlorothiazide, 0.03 microg/mL for amlodipine besylate, 0.03 microg/mL for indapamide, 0.02 microg.mL for nifedipine, and 0.01 microg/mL for lercanidipine hydrochloride. The suggested method has the advantage that all the drugs can be quantified alone or in combination with atenolol using a single mobile phase.