THE INTESTINAL ELIMINATION OF CIPROFLOXACIN IN THE RAT

The transepithelial intestinal elimination of ciprofloxacin was studie d in a rat model. Two and one ileal segment, along with their intact b lood supplies, were isolated and continuously perfused. Following a si ngle parenteral administration of 25 mg/kg ciprofloxacin, the drug in amounts of 1.97 +/- 0.70,1.88 +/- 0.99, and 1.44 +/- 0.77 mug/cm2 of m ucosal surface was recovered over 90 min from the proximal and distal jejunal loops and the ileal loop, respectively, reaching a calculated fraction of 6%-7% of the dose eliminated in the entire small intestine . The rate of intestinal elimination related linearly to the parentera l dose. In the proximal jejunum, however, doses >25 mg/kg were not acc ompanied by a concomitant increase in the eliminated fraction, suggest ing a saturable transport process. Parenterally administered probeneci d, amoxicillin, and nifedipine and changes ranging from 6.0 to 8.5 in the pH of the perfusates did not alter transepithelial elimination. Th is pathway of elimination of ciprofloxacin may play an important role in curing intestinal infections.