An HPLC method for the determination of lisinopril in human plasma and urine with fluorescence detection

A selective, sensitive and precise HPLC method with fluorimetric detection has been developed for the assay of lisinopril in human plasma and urine. The clean up of the sample was carried out by solid-phase extraction, firstly with C 18-cartridge and secondly with a silica-cartridge. After a pre-column derivatization with fluorescamine, the reaction mixture was chromatographed on C 18-column with gradient elution, using methanol and 0.02 M phosphate buffer (pH = 3.2). The fluorescamine–lisinopril derivative was detected fluorimetrically by monitoring the emission at 477 nm, with excitation at 383 nm. Linear quantitative response curve was generated over a concentration range of 5–200 ng/ml and 25–1000 ng/ml for plasma and urine samples, respectively. The mean recovery of lisinopril from plasma and urine was 63.41 and 74.08%, respectively. Intra-day and inter-day R.S.D. and R.M.E. values at three different concentrations were assessed. The method was applied for pharmacokinetic study in a healthy volunteer after a single oral dose of 20 mg of the drug.