The biliary excretion of cefazolin

Area of Science:

• Pharmacology
• Hepatobiliary Science

Background:

• Cefazolin is a widely used cephalosporin antibiotic.
• Understanding its biliary excretion is crucial for dosing and efficacy, especially in patients with liver or biliary tract conditions.

Purpose of the Study:

• To investigate the biliary excretion of cefazolin in both animal models and human subjects.
• To quantify cefazolin concentrations in bile and compare them to serum levels.

Main Methods:

• Isolated rabbit liver perfusion studies.
• Intravenous administration of cefazolin (500 mg) in normal human subjects and analysis of duodenal fluid.
• Analysis of bile samples collected during cholecystectomy in human patients.

Main Results:

• In rabbits, 6.7% of cefazolin was excreted into bile, with bile concentrations exceeding serum levels.
• In humans, peak cefazolin concentrations in duodenal fluid (17.10 ± 8.5 μg/ml) were observed 1-2 hours post-administration.
• Bile collected during cholecystectomy showed significantly higher cefazolin levels in common duct bile (31 ± 11 μg/ml) compared to gallbladder bile (5 ± 2 μg/ml) one hour after injection.

Conclusions:

• Cefazolin undergoes significant biliary excretion.
• Concentrations of cefazolin in bile are substantially higher than in serum, suggesting potential for biliary antimicrobial activity.
• Findings support the clinical relevance of cefazolin's biliary disposition.