title: Ultra-fast analysis of plasma and intracellular levels of HIV protease inhibitors in children: a clinical application of MALDI mass spectrometry.
abstract: 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 microL plasma and 1x10(6) 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 of these 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.
authors.affiliation: Department of Neurology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Jeroen J A
authors.initials: JJ
authors.lastname: van Kampen
authors.forename: Mariska L
authors.initials: ML
authors.lastname: Reedijk
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burgers
authors.forename: Lennard J M
authors.initials: LJ
authors.lastname: Dekker
authors.forename: Nico G
authors.initials: NG
authors.lastname: Hartwig
authors.forename: Ineke E
authors.initials: IE
authors.lastname: van der Ende
authors.forename: Ronald
authors.initials: R
authors.lastname: de Groot
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.forename: David M
authors.initials: DM
authors.lastname: Burger
authors.forename: Theo M
authors.initials: TM
authors.lastname: Luider
authors.forename: Rob A
authors.initials: RA
authors.lastname: Gruters
mesh_terms: D000293:Adolescent; D002648:Child; D002851:Chromatography, High Pressure Liquid; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology; D017320:HIV Protease Inhibitors / Q000097:blood* / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D061466:Lopinavir; D011744:Pyrimidinones / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D019438:Ritonavir / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; D061466:Lopinavir; D019438:Ritonavir