Rapid Simultaneous Determination of Olmesartan, —Amlodipine and Hydrochlorothiazide in Combined Pharmaceutical Dosage form by Stability-Indicating Ultra Performance Liquid Chromatography

A simple, precise and rapid stability-indicating ultra-performance liquid chromatography (UPLC) method was developed for the simultaneous quantitative determination of Olmesartan, Amlodipine and Hydrochlorothiazide from their innovative Pharmaceutical combination drug product, with the presence of degradation products. It involved a 50 mm × 2.1 mm, 1.8 μm Phenyl column. The separation was achieved on simple gradient method. The mobile phase A contains a mixture of sodium perchlorate buffer pH 3.2(0.053M): acetonitrile in the ratio 90:10, v/v, and mobile phase B contains a mixture of sodium perchlorate buffer pH 3.2(0.053M): acetonitrile in the ratio 10:90, v/v. The flow rate was 0.7 mL·min and column temperature was maintained at 55 ̊C.The gradient program (T/%B) was set as 0/10, 2/50, 4/80, and 6.0/10. The detector wavelength was 271 nm for Hydrochlorothiazide, 215 for Olmesartan and 237 nm for Amlodipine. The retention times of Olmesartan, Amlodipine, and Hydrochlorothiazide are 3.5, 3.3 and 0.9 minutes; respectively. The total runtime was 6.0 minutes within which three active compounds and their degradation products were separated. The described method was validated with respect to system suitability, specificity, linearity, precision and accuracy. The precision of the assay method was evaluated by carrying out six independent assays of Olmesartan, Amlodipine, and Hydrochlorothiazide (0.004 mg·mL, 0.001 mg·mL, 0.0025 mg·mL. The accuracy of the method was evaluated in triplicate at three concentration levels, i.e. 50%, 100%, and 150% of target test concentration. The described method was linear over the range, 2 to 6 μg·mL for Olmesartan, 0.5 to 1.5 μg·mL Amlodipine and 1.25 to 3.75 μg·mL for Hydrochlorothiazide. The method is fast and is suitable for high-throughput analysis of the drug and one can analyze about 240 samples per working day, facilitating the processing of large-number batch samples.