Using LC Retention Times in Organic Structure Determination: Drug Metabolite Identification

Drug Metab Lett. 2018;12(2):93-100. doi: 10.2174/1872312812666180802093347.

Abstract

Background: There is a continued need for improvements in the efficiency of metabolite structure elucidation.

Objective: We propose to take LC Retention Time (RT) into consideration during the process of structure determination.

Methods: Herein, we develop a simple methodology that employs a Chromatographic Hydrophobicity Index (CHI) framework for standardizing LC conditions and introduce and utilize the concept of a predictable CHI change upon Phase 1 biotransformation (CHIbt). Through the analysis of literature examples, we offer a Quantitative Structure-Retention Relationship (QSRR) for several types of biotransformation (especially hydroxylation) using physicochemical properties (clogP, hydrogen bonding).

Results: The CHI system for retention indexing is shown to be practical and simple to implement. A database of CHIbt values has been created from re-incubation of 3 compounds and from analysis of an additional 17 datasets from the literature. Application of this database is illustrated.

Conclusion: In our experience, this simple methodology allows complementing the discovery efforts that saves resources for in-depth characterization using NMR.

Keywords: CHI system; Drug metabolite identification; RT; RT prediction; liquid chromatography; mass spectrometry (MS)..

MeSH terms

  • Atorvastatin / metabolism*
  • Biotransformation
  • Carbanilides / metabolism*
  • Chromatography, Liquid / methods*
  • Demethylation
  • Humans
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Hydroxylation
  • Mass Spectrometry
  • Microsomes, Liver / metabolism
  • Molecular Structure
  • Oxidation-Reduction
  • Quantitative Structure-Activity Relationship
  • Time Factors
  • Workflow

Substances

  • Carbanilides
  • Atorvastatin
  • triclocarban