title: Quantification of N-acetyl-seryl-aspartyl-lysyl-proline in hemodialysis patients administered angiotensin-converting enzyme inhibitors by stable isotope dilution liquid chromatography-tandem mass spectrometry.
abstract: We developed a sensitive, selective and accurate method based on liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine N-terminal thymosin-β peptides of Ac-SDKP and Ac-ADKP in human plasma samples. Quantification of Ac-SDKP and Ac-ADKP was performed using solid phase extraction (SPE) based on C(18), reversed phase LC separation, and stable isotope dilution electrospray ionization-MS/MS in multiple reaction-monitoring (MRM) mode. The Ac-SDKP-(13)C(6), (15)N(2) and Ac-ADKP-d(7) were synthesized for the internal standards. These MRM monitoring ions were m/z 488→129 (quantitative ion)/226 for Ac-SDKP, m/z 496→137 for Ac-SDKP-(13)C(6), (15)N(2), m/z 472→129 (quantitative ion)/226 for Ac-ADKP, and m/z 479→129 for Ac-ADKP-d(7), respectively. Lower limit of quantitation (LLOQ) of Ac-SDKP and Ac-ADKP was 0.1ng/mL in human plasma. Recovery values were ranged from 94.7% to 106.3% for inter- (RSD: 0.6-3.5%) and intra- (RSD: 0.4-4.9%) day assays. Plasma Ac-SDKP levels were significantly higher in hemodialyzed subjects treated with angiotensin-converting enzyme inhibitors of enalapril (27.3±24.6ng/mL, n=10) and trandolapril (12.3±16.9ng/mL, n=18) than healthy (0.4±0.2ng/mL, n=7) and hemodialyzed subjects (0.6±0.2ng/mL, n=34). This analytical method would be useful to measure N-terminal thymosin-β peptides in human plasma for the clinical study.
authors.affiliation: Department of Physical and Analytical Chemistry, School of Pharmacy, Kinjo Gakuin University, Omori, Moriyama-ku, Nagoya, Aichi, Japan. kinoue@kinjo-u.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Inoue
authors.forename: Ayaka
authors.initials: A
authors.lastname: Ikemura
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Tsuruta
authors.forename: Kazuki
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kaname
authors.initials: K
authors.lastname: Tsutsumiuchi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Hino
authors.forename: Hisao
authors.initials: H
authors.lastname: Oka
mesh_terms: D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy* / Q000209:etiology; D007201:Indicator Dilution Techniques; D008297:Male; D008875:Middle Aged; D009587:Nitrogen Isotopes; D009842:Oligopeptides / Q000097:blood* / Q000737:chemistry; D010446:Peptide Fragments / Q000097:blood / Q000737:chemistry; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D013947:Thymosin / Q000378:metabolism
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D009842:Oligopeptides; D010446:Peptide Fragments; C557485:acetyl-alanyl-aspartyl-lysyl-proline; D013947:Thymosin; D003903:Deuterium; C058504:goralatide