Simultaneous determination of some illegal antihypertensive and diuretic drugs in traditional herbal preparations by HPLC-DAD

A simple, stable, and specific high-performance liquid chromatography coupled with a DAD detector (HPLC-DAD) method has been developed and validated for the simultaneous determination of amlodipine, felodipine, furosemide, nifedipine, and spironolactone in traditional herbal products. The analytes were extracted in acetonitrile: water (50 : 50, v/v) with help of the ultrasonic. The separation of analytes was performed in an Apollo C18 column (250 × 4.6 mm; 5 µm) and a mobile phase consisting of mixture acetonitrile: 0.1% phosphoric acid in gradient elution. The analyzed drugs were detected at 238 nm.