Validation of a fast liquid chromatography–UV method for the analysis of drugs used in combined cardiovascular therapy in human plasma

Ultra-performance liquid chromatography (UPLC) was investigated as a faster alternative to high-performance liquid chromatography (HPLC) for the simultaneous analysis of drugs usually prescribed in cardiovascular therapy. Upon a previously developed and validated solid phase extraction (SPE)–HPLC–photodiode array (PDA)–fluorescence (FLR) method, separation of chlorthalidone (CLTD; diuretic), valsartan and its metabolite (VAL and VAL-M1 respectively; angiotensin II receptor antagonist drugs) and fluvastatin (FLUV; statin) was performed in human plasma using an RP C18 column (50 mm × 2.1 mm, 1.7 μm, Waters Acquity UPLC™ (BEH)) and a tunable UV–vis (TUV) detector. After method transfer, different system variables were modulated to study the evolution of responses of the analytes and the endogenous interferences. The improved method was fully validated and the results were compared with its precursor HPLC method relating to analysis time, efficiency and sensitivity. The studied compounds were separated in less than 8 min and the method showed good linearity (20–3000 μg/L for chlorthalidone, 110–1100 μg/L for valsartan-M1, 67–1900 μg/L for valsartan and 48–1100 μg/L for fluvastatin), precision and accuracy. The proposed method was found to be reproducible (RSD < 10%), accurate (RE < 15%), robust and suitable for quantitative analysis of the studied drugs in plasma obtained from patients under combined cardiovascular treatment.