Discovery of efficacious Pseudomonas aeruginosa-targeted siderophore-conjugated monocarbams by application of a semi-mechanistic pharmacokinetic/pharmacodynamic model

J Med Chem. 2015 Mar 12;58(5):2195-205. doi: 10.1021/jm501506f. Epub 2015 Mar 3.

Abstract

To identify new agents for the treatment of multi-drug-resistant Pseudomonas aeruginosa, we focused on siderophore-conjugated monocarbams. This class of monocyclic β-lactams are stable to metallo-β-lactamases and have excellent P. aeruginosa activities due to their ability to exploit the iron uptake machinery of Gram-negative bacteria. Our medicinal chemistry plan focused on identifying a molecule with optimal potency and physical properties and activity for in vivo efficacy. Modifications to the monocarbam linker, siderophore, and oxime portion of the molecules were examined. Through these efforts, a series of pyrrolidinone-based monocarbams with good P. aeruginosa cellular activity (P. aeruginosa MIC90 = 2 μg/mL), free fraction levels (>20% free), and hydrolytic stability (t1/2 ≥ 100 h) were identified. To differentiate the lead compounds and enable prioritization for in vivo studies, we applied a semi-mechanistic pharmacokinetic/pharmacodynamic model to enable prediction of in vivo efficacy from in vitro data.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacokinetics*
  • Anti-Bacterial Agents / pharmacology*
  • Drug Discovery*
  • Humans
  • Male
  • Monobactams / chemistry
  • Monobactams / pharmacokinetics*
  • Monobactams / pharmacology*
  • Pseudomonas Infections / drug therapy*
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / drug effects*
  • Rats
  • Rats, Wistar
  • Siderophores / metabolism*
  • Structure-Activity Relationship
  • beta-Lactamases / chemistry

Substances

  • Anti-Bacterial Agents
  • Monobactams
  • Siderophores
  • beta-Lactamases