Analysis of multi-site drug-protein interactions by high-performanceaffinity chromatography: Binding by glimepiride to normal orglycated human serum albumin

Ryan Matsuda, Zhao Li, Xiwei Zheng, David S. Hage

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

High-performance affinity chromatography (HPAC) was used in a variety of formats to examine multi-siteinteractions between glimepiride, a third-generation sulfonylurea drug, and normal or in vitro glycatedforms of the transport protein human serum albumin (HSA). Frontal analysis revealed that glimepirideinteracts with normal HSA and glycated HSA at a group of high affinity sites (association equilibriumconstant, or Ka, 9.2-11.8 × 105M-1at pH 7.4 and 37°C) and a group of lower affinity regions (Ka,5.9-16 × 103M-1). Zonal elution competition studies were designed and carried out in both normal-and reversed-role formats to investigate the binding by this drug at specific sites. These experimentsindicated that glimepiride was interacting at both Sudlow sites I and II. Allosteric effects were also notedwith R-warfarin at Sudlow site I and with tamoxifen at the tamoxifen site on HSA. The binding at Sudlowsite I had a 2.1-to 2.3-fold increase in affinity in going from normal HSA to the glycated samples of HSA. There was no significant change in the affinity for glimepiride at Sudlow site II in going from normal HSAto a moderately glycated sample of HSA, but a slight decrease in affinity was seen in going to a morehighly glycated HSA sample. These results demonstrated how various HPAC-based methods can be usedto profile and characterize multi-site binding by a drug such as glimepiride to a protein and its modifiedforms. The information obtained from this study should be useful in providing a better understandingof how drug-protein binding may be affected by glycation and of how separation and analysis methodsbased on HPAC can be employed to study systems with complex interactions or that involve modifiedproteins.

Original languageEnglish (US)
Pages (from-to)133-144
Number of pages12
JournalJournal of Chromatography A
Volume1408
DOIs
StatePublished - 2015

Keywords

  • Drug-protein binding
  • Glimepiride
  • Glycation
  • High-performance affinity chromatography
  • Human serum albumin

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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