Development and validation of samples stabilization strategy and LC-MS/MS method for simultaneous determination of clevidipine and its primary metabolite in human plasma: Application to clinical pharmacokinetic study in Chinese healthy volunteers.

A feasible LC-MS/MS method with reliable stabilizers consisted of sodium fluoride, ascorbic acid and formic acid was developed and validated for the determination of clevidipine and its primary metabolite (H152/81) in human plasma. Sodium fluoride existing in the vacutainer tubes was used to inhibit esterase activity to protect the clevidipine from hydrolysis as soon as blood was collected. Ascorbic acid and formic acid were added to the separated plasma samples to avoid the oxidation and further hydrolysis of clevidipine and H152/81. The further sample preparation was accomplished through a single step liquid-liquid extraction (LLE) by ethyl acetate. The chromatography separation was carried out on an ACE Excel 3 μm SuperC18 (2.1 × 50 mm, id, ACE, United Kingdom) column with gradient elution using 10 mM ammonium acetate water solution and methanol as the mobile phase. Detection was performed in the negative ion electrospray ionization mode using multiple reaction monitoring (clevidipine: m/z 454.1 → 234.0; clevidipine-d7: m/z 461.1 → 240.1; H152/81: m/z 354.0 → 208.0; H152/81-CD: m/z 358.0 → 212.0). The method exhibited good linearity over the concentration ranges of 0.100 to 40.0 ng/mL for clevidipine and 5.00 to 400 ng/mL for H152/81. The intra- and inter-batch precision and accuracy of clevidipine and H152/81 were all within the acceptable criteria. The method was successfully applied to a pharmacokinetic study of clevidipine and H152/81 in healthy Chinese volunteers following 8 mg/h intravenous infusion of clevidipine butyrate injectable emulsion for 0.5 h. The results showed that clevidipine was rapidly eliminated with a short half-life time of 0.244 ± 0.125 h and a maximum concentration of 25.2 ± 7.09 ng/mL. H152/81 was detectable in the plasma samples up to 48.5 h with a half-life time of 10.7 ± 2.30 h and a maximum plasma concentration of 301 ± 38.1 ng/mL.