Prediction and in vitro evaluation of selected protease inhibitor antiviral drugs as inhibitors of carboxylesterase 1: a potential source of drug-drug interactions

Pharm Res. 2012 Apr;29(4):972-82. doi: 10.1007/s11095-011-0637-9. Epub 2011 Dec 9.


Purpose: To predict and determine whether the protease inhibitors (PIs) nelfinavir, amprenavir, atazanavir, ritonavir, and saquinavir could serve as metabolic inhibitors of the human CES1 (hCES1) using both molecular modeling techniques and in vitro inhibition assays.

Methods: Initially, a molecular modeling approach was utilized to predict whether the selected PIs could serve as hCES1 inhibitors. The inhibitory effects of these PIs on hCES1 activity were then further evaluated utilizing previously established in vitro assay.

Results: Pharmacophore and 2D-QSAR modeling predicted that nelfinavir would serve as a potent hCES1 inhibitor. This hypothesis was validated by in vitro hCES1 inhibition studies. Other PIs (amprenavir, atazanavir, ritonavir, saquinavir) were evaluated and also shown to be hCES1 inhibitors in vitro, although substantially less potent relative to nelfinavir.

Conclusion: Computational molecular modeling is a valid approach to identify potential hCES1 inhibitors as candidates for further assessment using validated in vitro techniques. DDIs could occur when nelfinavir is co-administered with drugs metabolized by hCES1.

MeSH terms

  • Antiviral Agents / chemistry
  • Antiviral Agents / pharmacology*
  • Atazanavir Sulfate
  • Carbamates / chemistry
  • Carbamates / pharmacology
  • Carboxylic Ester Hydrolases / antagonists & inhibitors*
  • Carboxylic Ester Hydrolases / chemistry
  • Carboxylic Ester Hydrolases / metabolism
  • Drug Interactions
  • Furans
  • Humans
  • Kinetics
  • Models, Molecular
  • Nelfinavir / chemistry
  • Nelfinavir / pharmacology
  • Oligopeptides / chemistry
  • Oligopeptides / pharmacology
  • Protease Inhibitors / chemistry
  • Protease Inhibitors / pharmacology*
  • Pyridines / chemistry
  • Pyridines / pharmacology
  • Quantitative Structure-Activity Relationship
  • Ritonavir / chemistry
  • Ritonavir / pharmacology
  • Saquinavir / chemistry
  • Saquinavir / pharmacology
  • Sulfonamides / chemistry
  • Sulfonamides / pharmacology


  • Antiviral Agents
  • Carbamates
  • Furans
  • Oligopeptides
  • Protease Inhibitors
  • Pyridines
  • Sulfonamides
  • Atazanavir Sulfate
  • amprenavir
  • Carboxylic Ester Hydrolases
  • CES1 protein, human
  • Nelfinavir
  • Saquinavir
  • Ritonavir