Antimicrobial activity, safety and pharmacokinetics evaluation of PMTM: A novel pleuromutilin candidate

Area of Science:

• Microbiology
• Pharmacology
• Drug Development

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant global public health threat due to high mortality rates.
• There is an urgent need for novel antibacterial agents effective against resistant bacterial strains.

Purpose of the Study:

• To evaluate the in vitro antibacterial efficacy of the pleuromutilin compound PMTM against MRSA.
• To assess the preclinical safety profile of PMTM.
• To explore the potential of PMTM as a drug candidate for MRSA infections.

Main Methods:

• In vitro antibacterial assays to determine anti-MRSA activity and post-antibiotic effect (PAE).
• Assessment of resistance development potential.
• In vitro and in vivo safety evaluations, including cytotoxicity, hemolytic activity, acute oral toxicity, mutagenicity, CYP3A4 inhibition, and hERG K+ channel inhibition.
• Preparation and characterization of PMTM salts (sulfate and hydrochloride).
• Pharmacokinetic studies of the PMTM sulfate salt in mice.

Main Results:

• PMTM demonstrated high anti-MRSA activity, a notable PAE, and limited resistance development potential.
• PMTM exhibited low cytotoxicity, low hemolytic activity, tolerable acute oral toxicity, no mutagenicity, and weak CYP3A4 inhibition.
• PMTM showed moderate hERG K+ channel inhibition.
• The PMTM sulfate salt displayed superior solubility and improved pharmacokinetic parameters, including oral bioavailability in mice.

Conclusions:

• PMTM is a promising antibacterial agent with significant potential for treating MRSA infections.
• The PMTM sulfate salt is a viable formulation for further drug development due to its favorable solubility and pharmacokinetic properties.
• This study establishes a solid foundation for the advancement of PMTM as a novel antibacterial therapeutic.