title: Quantitative determination of irinotecan and the metabolite SN-38 by nanoflow liquid chromatography-tandem mass spectrometry in different regions of multicellular tumor spheroids.
abstract: A new and simple method was developed to evaluate the distribution of therapeutics in three-dimensional multicellular tumor spheroids (MCTS) by combining serial trypsinization and nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). This methodology was validated with quantitative measurements of irinotecan and its bioactive metabolite, SN-38, in distinct spatial regions of HCT 116 MCTS. Irinotecan showed a time-dependent permeability into MCTS with most of the drug accumulating in the core after 24 h of treatment. The amount of SN-38 detected was 30 times lower than that of the parent drug, and was more abundant in the outer rim and intermediate regions of MCTS where proliferating cells were present. This method can be used to investigate novel and established drugs. It enables investigation of drug penetration properties and identification of metabolites with spatial specificity in MCTS. The new approach has great value in facilitating the drug evaluation process.
authors.affiliation: Department of Chemistry and Biochemistry, Harper Cancer Research Institute, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN, 46556, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Amanda B
authors.initials: AB
authors.lastname: Hummon
mesh_terms: D002166:Camptothecin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D045325:HCT116 Cells; D006801:Humans; D000077146:Irinotecan; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018874:Spheroids, Cellular / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014407:Tumor Cells, Cultured / Q000378:metabolism*
chemical_list: D000077146:Irinotecan; D002166:Camptothecin