Simultaneous Quantitation of Amlodipine Besylate and Olmesartan Medoxomil in Fixed-Dose Combination Tablets: HPLC-DAD Versus UHPLC-DAD.

Association of amlodipine besylate and olmesartan medoxomil in fixed-dose combination tablets is effective, safe and well tolerated for the treatment of hypertension. The aim of this study was to optimize and validate a novel and fast UHPLC-DAD method for simultaneous quantification of these antihypertensive drugs in tablets, using a transfer procedure from a conventional HPLC-DAD method. The HPLC separation was carried out using a C18 column (150 × 4.6 mm2; 5 μm) and a mobile phase composed of acetonitrile, methanol and 0.3% trimethylamine pH 2.75 (30:30:40), at 1.0 mL/min. UV detection was performed at 238 nm and injection volume was 10 μL. Then, the analytical method was transferred to UHPLC, using a BEH C18 column (50 × 2.1 mm2; 1.7 μm). Mathematical equations were applied to calculate the UHPLC mobile phase flow rate and injection volume, which were 0.613 mL/min and 0.7 μL, respectively. UHPLC method was fully validated and showed to be selective, linear (r2 > 0.99), precise (RSD < 2.0%), accurate and robust. UHPLC method was statistically equivalent to the HPLC method after analysis of three batches of BenicarAnlo® tablets. However, UHPLC method promoted faster analyses, better chromatographic performance and lower solvent consumption.