Development and validation of a liquid chromatography-tandem mass spectrometry method for determination of ibuprofen in human plasma

Ibuprofen is widely used to reduce fever, pain, and inflammation and in the treatment of patent ductus arteriosus (PDA) in preterm infants. However, to study the impact of pharmacokinetics of ibuprofen on the rate of ductus arteriosus closure in humans, a quantitative method is required. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a highly sensitive, accurate, reliable, fast, and simple bioanalytical method. In this study, we developed and utilized an LC-MS/MS method to determine ibuprofen bioavailability. One of the novel aspects of this work is the small specimen volume required for the analysis (i.e., 50 mu L). The calibration curve was linear across a concentration range of 0.15-50 mu g/mL. The coefficient of variation for intra-day and inter-day precision was within 0.78%-7.21% and accuracy was within 97.52%-107.21% of the nominal values for low, medium, and high quality control (QC) concentration levels-QCL, QCM, and QCH (0.45, 9.0, and 40.0 mu g/mL, respectively). For ibuprofen concentrations at the lower limit of quantitation (LLOQ), intra-day and inter-day accuracy were 98.11% and 99.81%, respectively; however, the intra-day and inter-day precision were 1.89% and 5.37%, respectively. The pharmacokinetic study involved 18 neonatal subjects who were grouped into low- or high-dose ibuprofen groups. The median maximum concentration for low- and high-dose regimens were 16.05 (14.21-19.32) and 24.10 (20.63-32.03) mu g/mL, respectively, and the median elimination rate constant was 0.041 (0.026-0.047) and 0.071 (0.050-0.073) h(-1), respectively. Thus, the fully validated LC-MS/MS method was determined to be suitable for analyzing unknown plasma samples for ibuprofen pharmacokinetic, bioavailability, and bioequivalence studies. (C) 2019 The Association for Mass Spectrometry: Applications to the Clinical Lab (MSACL). Published by Elsevier B.V. All rights reserved.