Ionic liquids dispersive liquid-liquid microextraction and high-performance liquid chromatographic determination of irbesartan and valsartan in human urine.

An environmentally friendly ionic liquids dispersive liquid-liquid microextraction (IL-DLLME) method coupled with high-performance liquid chromatography (HPLC) for the determination of antihypertensive drugs irbesartan and valsartan in human urine samples was developed. The HPLC separations were accomplished in less than 10 min using a reversed-phase C(18) column (250 × 4.60 mm i.d., 5 µm) with a mobile phase containing 0.3 % formic acid solution and methanol (v/v, 3:7; flow rate, 1.0 mL/min). UV absorption responses at 236 nm were linear over a wide concentration range from 50 µg/mL to the detection limits of 3.3 µg/L for valsartan and 1.5 µg/L for irbesartan. The effective parameters on IL-DLLME, such as ionic liquid types and their amounts, disperser solvent types and their volume, pH of the sample and extraction time were studied and optimized. The developed IL-DLLME-HPLC was successfully applied for evaluation of the urine irbesartan and valsartan profile following oral capsules administration.