Pharmacokinetics of cefuroxime and ciprofloxacin in gastric mucosa: comparison to in vitro inhibitory concentrations against Helicobacter pylori.

Antibiotic concentrations in serum and gastric mucosa were measured in a previously described animal model (Antimicrob Agents Chemother 1990; 34:25-28) using a high-pressure liquid chromatography (HPLC) technique. Cefuroxime 30 mg/kg, and Ciprofloxacin 20 mg/kg were given by intramuscular injection. Cefuroxime showed a bimodal tissue concentration curve with an initial mucosal peak of 2.97 micrograms/g at 1 hour. After falling to undetectable levels, a second peak of 1.47 micrograms/g occurred at 8 hours. The corresponding mucosa/serum ratio was 36.75. Ciprofloxacin tissue levels peaked at 0.33 microgram/g at 1 hour. The concentration curve was again bimodal with a fall at 2 hours followed by a second peak of 0.61 microgram/g at 4 hours. The mucosa/serum ratio was highest (1.69) 4 hours post injection. The bimodal tissue concentration curves seen for both antibiotics suggest the presence of two different transport mechanisms in the gastric mucosa. None of the antibiotics had tissue levels that consistently exceeded known MIC90 for Helicobacter pylori.