Quantification of pantoprazole in human plasma using LC-MS/MS for pharmacokinetics and bioequivalence study

A highly sensitive and rapid method for the analysis of pantoprazole in human plasma using liquid chromatography coupled to tandem electrospray ionization mass spectrometry was developed. The procedure involves a simple protein precipitation method with methyl alcohol and separation by RP-HPLC. Detection was performed by positive ion electrospray ionization in multiple reaction monitoring mode, monitoring the transitions m/z 384.1→200.0 and m/z 346.1→198.0, for quantification of pantoprazole and IS, respectively. The standard calibration curves showed good linearity within the range of 5-5,000 ng mL(-1). The lower limit of quantitation (LLOQ) was about 5 ng mL(-1). The extractive recovery of pantoprazole from the biological matrix was more than 77.58% and the matrix effect was complied with relevant provision. The intra-day accuracy of the drug containing serum samples was more than 92.19% with a precision of 0.79-5.36%. The inter-day accuracy was 85.49% or more, with a precision of 0.91-12.67%. Intra and inter-day accuracy of the assay at four concentrations were 97.9-98.2% with a precision of 4.2-13.9%. This method offered good precision and accuracy and was successfully applied to the pharmacokinetic and bioequivalence studies of 40 mg of enteric-coated pantoprazole in 20 healthy Chinese volunteers.