Metabolism studies of a small-molecule tumor necrosis factor-alpha (TNF-α) inhibitor, UTL-5b (GBL-5b)

  • Jiajiu Shaw
  • Brian Shay
  • Jack Jiang
  • Frederick Valeriote
  • Ben Chen
Original Paper

Abstract

UTL-5b is an anti-inflammatory and anti-arthritic small-molecule tumor necrosis factor-alpha inhibitor and a structural analogue of the anti-arthritic drug, leflunomide. Leflunomide is known to be metabolized to teriflunomide, but the metabolites of UTL-5b have not been reported. The objective of this study was to investigate whether UTL-5b has a similar metabolic behavior as leflunomide. Preliminary studies showed that when exposed to microsomes in vitro with or without NADPH, UTL-5b disappeared within 30 min. To further investigate the microsomal metabolism, liquid chromatography-ultraviolet (LC-UV) and LC/tandem mass spectrometry (LC–MS/MS) were employed to, respectively, monitor the microsomal metabolites and identify the structure of the metabolites using LC-full scan MS and LC combined with multiple-ion monitoring MS. Fragmentation determination was analyzed by two types of scans: product ion scans and precursor ion scan. The in vitro microsomal treatment of UTL-5b resulted in two major metabolites: 5-methylisoxazole-3-carboxylic acid and 2-chloroaniline. Thus, the in vitro metabolic behavior of UTL-5b appears to be different from that of leflunomide in that the isoxazole ring is cleaved.

Keywords

Microsome Metabolites LC–MS/MS TNF-α inhibitor UTL-5b 

Abbreviations

DHODH

Dihydroorotate dehydrogenase

ESI

Electrospray ionization

HPLC

High performance liquid chromatography

LC

Liquid chromatography

LC–MS/MS

Liquid chromatography/tandem mass spectrometry

MIM

Multiple ion monitoring

MS

Mass spectrometry/mass spectrometer

NMR

Nuclear magnetic resonance

Rt

Retention time

SIR

Single ion recording

TIC

Total ion current

TNF-α

Tumor necrosis factor-alpha

UV

Ultraviolet

Copyright information

© Springer-Verlag France 2011

Authors and Affiliations

  • Jiajiu Shaw
    • 1
    • 6
  • Brian Shay
    • 2
  • Jack Jiang
    • 3
  • Frederick Valeriote
    • 4
  • Ben Chen
    • 5
  1. 1.Unitech Pharmaceuticals, Inc.Ann ArborUSA
  2. 2.Department of ChemistryWayne State UniversityDetroitUSA
  3. 3.GeneBlue CorporationSan GabrielUSA
  4. 4.Department of Internal MedicineHenry Ford Health SystemDetroitUSA
  5. 5.Department of Internal MedicineWayne State UniversityDetroitUSA
  6. 6.21st Century Therapeutic, Inc.FerndaleUSA

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