Bronchoscopic microsampling method for measuring drug concentration in epithelial lining fluid.

Area of Science:

• Pharmacokinetics
• Pulmonary Medicine
• Medical Technology

Background:

• Optimizing antimicrobial dosing for respiratory tract infections requires direct measurement of drug concentrations at the infection site.
• Bronchial epithelial lining fluid (ELF) is a key site for drug penetration in lung infections.

Purpose of the Study:

• To determine the time-concentration profile of levofloxacin in ELF following oral administration.
• To evaluate the feasibility and safety of bronchoscopic microsampling for repeated drug concentration measurements in ELF.

Main Methods:

• Oral administration of levofloxacin to healthy volunteers.
• Repeated sampling of ELF using novel bronchoscopic microsampling probes.
• Simultaneous measurement of levofloxacin concentrations in serum and ELF.
• Comparison of ELF concentrations with minimal inhibitory concentrations (MICs) of common respiratory pathogens.

Main Results:

• Levofloxacin reached 43.4% of serum concentration in ELF at 1 hour, achieving parity at 2 hours.
• ELF concentrations exceeded MICs for Staphylococcus aureus, Klebsiella spp., and Haemophilus influenzae for at least 6 hours.
• The bronchoscopic microsampling procedure was well-tolerated with no observed complications.

Conclusions:

• Bronchoscopic microsampling is a safe and feasible method for directly measuring antimicrobial concentrations in ELF.
• This technique enables precise pharmacokinetic profiling in the target site for respiratory infections.
• The findings support the use of this method for guiding antimicrobial dosing strategies.