title: Calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry assays and its application in supporting microdose absolute bioavailability studies.
abstract: A methodology for the accurate calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) assays and its application in supporting microdose absolute bioavailability studies are reported for the first time. For simplicity, this calculation methodology and the strategy to minimize the isotopic interference are demonstrated using a simple molecule entity, then applied to actual development drugs. The exact isotopic interferences calculated with this methodology were often much less than the traditionally used, overestimated isotopic interferences simply based on the molecular isotope abundance. One application of the methodology is the selection of a stable isotopically labeled internal standard (SIL-IS) for an LC-MS/MS bioanalytical assay. The second application is the selection of an SIL analogue for use in intravenous (i.v.) microdosing for the determination of absolute bioavailability. In the case of microdosing, the traditional approach of calculating isotopic interferences can result in selecting a labeling scheme that overlabels the i.v.-dosed drug or leads to incorrect conclusions on the feasibility of using an SIL drug and analysis by LC-MS/MS. The methodology presented here can guide the synthesis by accurately calculating the isotopic interferences when labeling at different positions, using different selective reaction monitoring (SRM) transitions or adding more labeling positions. This methodology has been successfully applied to the selection of the labeled i.v.-dosed drugs for use in two microdose absolute bioavailability studies, before initiating the chemical synthesis. With this methodology, significant time and cost saving can be achieved in supporting microdose absolute bioavailability studies with stable labeled drugs.
authors.affiliation: Bioanalytical Sciences, Research and Development, Bristol-Myers Squibb, Route 206 and Province Line Road, Princeton, New Jersey 08543, United States. huidong.gu@bms.com
authors.forename: Huidong
authors.initials: H
authors.lastname: Gu
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Aubry
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.forename: Jianing
authors.initials: J
authors.lastname: Zeng
authors.forename: John
authors.initials: J
authors.lastname: Easter
authors.forename: Jun-sheng
authors.initials: JS
authors.lastname: Wang
authors.forename: Randy
authors.initials: R
authors.lastname: Dockens
authors.forename: Marc
authors.initials: M
authors.lastname: Bifano
authors.forename: Richard
authors.initials: R
authors.lastname: Burrell
authors.forename: Mark E
authors.initials: ME
authors.lastname: Arnold
mesh_terms: D001682:Biological Availability; D002219:Carbamates; D002247:Carbon Isotopes / Q000032:analysis; D002853:Chromatography, Liquid; D017022:Flow Injection Analysis; D006801:Humans; D007093:Imidazoles / Q000493:pharmacokinetics*; D009587:Nitrogen Isotopes / Q000032:analysis; D010069:Oxadiazoles / Q000493:pharmacokinetics*; D011759:Pyrrolidines; D012015:Reference Standards; D013449:Sulfonamides / Q000493:pharmacokinetics*; D053719:Tandem Mass Spectrometry; D014633:Valine / Q000031:analogs & derivatives
chemical_list: C554092:BMS 708163; D002219:Carbamates; D002247:Carbon Isotopes; D007093:Imidazoles; D009587:Nitrogen Isotopes; D010069:Oxadiazoles; D011759:Pyrrolidines; D013449:Sulfonamides; D014633:Valine; C549273:daclatasvir