A Validated LC–MS/MS Method for Unbound Rifapentine Quantitation Reveals Nonlinear Plasma Protein Binding and Comparable Free Fractions Between Adults and Children with Tuberculosis

Key Points

• Nonlinear plasma protein binding of rifapentine impacts the drug's efficacy and safety profile.
• Free fractions of rifapentine were similar between adults and children, indicating consistent therapeutic effects.
• Assessment involved a validated LC–MS/MS method for accurate quantitation of unbound rifapentine levels.
• Understanding these binding characteristics can improve tuberculosis treatment strategies for diverse age groups.