RAPID DETERMINATION OF CANDESARTAN IN HUMAN PLASMA BY LIQUID CHROMATOGRAPHY TANDEM MASS SPECTROMETRY AND ITS APPLICATION TO A BIOEQUIVALENCE STUDY

Abstract

A highly sensitive and simple LC-MS/MS method after one-step protein precipitation was developed and validated for determination of candesartan in human plasma using irbesartan as the internal standard (IS). The analyte and IS were separated by a gradient program with a mobile phase consisting of 0.1% formic acid (containing 2 mM ammonium acetate) and methanol at a flow rate of 0.30 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer via electrospray ionization in the positive ion mode. Selected reaction monitoring using the precursor → product ion combinations of m/z 441.0 → 263.0 and m/z 429.5 → 195.0 were used to quantify candesartan and IS, respectively. The method was validated and proved to be linear, accurate, and precise over the range of 2–200 ng/mL. The lower limit of quantification of candesartan was 2 ng/mL. Validation results indicated that intra-day and inter-day precision was ≤7.34% and ≤8.02%, respectively. The accuracy was from −4.53% to 4.28%. The validated method was successfully applied to a randomized, two-period cross-over bioequivalence study in 20 healthy Chinese volunteers following a single oral dose of 8 mg candesartan cilexetil. The simple, inexpensive protein precipitation and high-throughput method makes it a suitable and valuable tool in the investigation of the clinical pharmacokinetics and bioequivalence.