Simultaneous estimation of hydrochlorothiazide, amlodipine, and losartan in tablet dosage form by RP-HPLC

A simple, sensitive and specific liquid chromatographic method with UV detection (230 nm) was developed for the simultaneous estimation of hydrochlorothiazide, amlodipine and losartan in tablet dosage form and telmisartan as an internal standard. Separation was achieved with a phenomenex luna 5μ CN 100R, 250 × 4.60 mm 5 micron size column, ambient temperature with a low pressure gradient mode with mobile phase containing acetonitrile, water and 0.4% of potassium dihydrogen phosphate buffer pH 2.7 adjusted with orthophosphoric acid (45:35:20). The flow rate was 1 mL min⁻¹ and eluent was monitored at 230 nm. The selected chromatographic conditions were found to effectively separate hydrochlorothiazide, amlodipine and losartan with retention time of 3.9, 4.9 and 5.8 min respectively. The linearity range of hydrochlorothiazide, amlodipine and losartan found in the range of 12.5–62.5 μg ml⁻¹, 2.5–12.5 μg ml⁻¹ and 50–250 μg ml⁻¹ respectively. The proposed method was found to be accurate, precise, reproducible and specific and it can also be used for routine quality-control analysis of these drugs in combination tablets.