Simultaneous determination of ivabradine and N-desmethylivabradine in human plasma and urine using a LC-MS/MS method: application to a pharmacokinetic study

摘要

AbstractA sensitive and specific liquid-chromatography tandem mass spectrometry (LC-MS/MS) assay has been developed and validated for the simultaneous quantification of ivabradine and its active metabolite N-desmethylivabradine in human plasma and urine. The assay employed a single liquid–liquid extraction of the analytes from plasma and urine samples, and diazepam was used as internal standard (IS). The chromatographic separation was achieved on a Diamonsil C₁₈ column (150?mm×4.6?mm, 5?μm, Dikma) using a mixture of methanol and aqueous 5?mM ammonium acetate buffer containing 0.2% formic acid (80:20, v/v) as mobile phase. The assay for ivabradine and N-desmethylivabradine in plasma showed good linearity (r≥0.99) over the ranges 0.1013–101.3?ng/mL and 0.085–25.5?ng/mL, respectively. The assay for ivabradine and N-desmethylivabradine in urine showed good linearity (r≥0.99) over the ranges 10.13–6078?ng/mL and 8.5–850?ng/mL, respectively. The intra- and inter-day accuracy and precision values were found to be within the assay variability limits (RSD