HIV protease inhibitors must penetrate into cells to exert their action. Differences in the intracellular pharmacokinetics of these drugs may explain why some patients fail on therapy or suffer from drug toxicity. Yet, there is no information available on the intracellular levels of HIV protease inhibitors in HIV infected children, which is in part due to the large amount of sample that is normally required to measure the intracellular concentrations of these drugs. Therefore, we developed an ultra-fast and sensitive assay to measure the intracellular concentrations of HIV protease inhibitors in small amounts of peripheral blood mononuclear cells (PBMCs), and determined the intracellular concentrations of lopinavir and ritonavir in HIV infected children. An assay based on matrix-assisted laser desorption/ionization (MALDI) - triple quadrupole mass spectrometry was developed to determine the concentrations of HIV protease inhibitors in 10 μL plasma and 1 × 106 PBMCs. Precisions and accuracies were within the values set by the FDA for bioanalytical method validation. Lopinavir and ritonavir did not accumulate in PBMCs of HIV infected children. In addition, the intracellular concentrations of lopinavir and ritonavir correlated poorly to the plasma concentrations ofthese drugs. MALDI-triple quadrupole mass spectrometry is a new tool for ultra-fast and sensitive determination of drug concentrations which can be used, for example, to assess the intracellular pharmacokinetics of HIV protease inhibitors in HIV infected children.

Additional Metadata
Keywords Human immunodeficiency virus 1 infection, Human immunodeficiency virus infection, Human immunodeficiency virus proteinase inhibitor, abacavir, adolescent, article, bioaccumulation, cell level, child, childhood disease, clinical article, clinical practice, controlled study, drug blood level, drug determination, drug monitoring, emtricitabine, female, food and drug administration, high performance thin layer chromatography, human, human cell, instrument validation, intermethod comparison, lamivudine, lopinavir, lopinavir plus ritonavir, male, matrix assisted laser desorption ionization time of flight mass spectrometry, peripheral blood mononuclear cell, plasma concentration-time curve, process development, quantitative analysis, ritonavir, school child, sensitivity and specificity, tenofovir
Persistent URL dx.doi.org/10.1371/journal.pone.0011409, hdl.handle.net/1765/21030
Citation
van Kampen, J.J.A., Reedijk, M.L., Burgers, P.C., Dekker, L.J.M., Hartwig, N.G., van der Ende, I.E., … Gruters, R.A.. (2010). Ultra-fast analysis of plasma and intracellular levels of HIV protease inhibitors in children: A clinical application of MALDI mass spectrometry. PLoS ONE, 5(7), 1–9. doi:10.1371/journal.pone.0011409