Decreased ciprofloxacin absorption with concomitant administration of ferrous fumarate

The effect of ferrous fumarate on the relative bioavailability of ciprofloxacin after a single 500 mg oral dose of ciprofloxacin was studied in eight healthy males. Blood samples were collected at regular intervals 0-24 h post-dose. Urine was collected during 24 h to determine the cumulative urine excretion of ciprofloxacin. Ciprofloxacin concentrations in serum and urine were determined by high pressure liquid chromatography. Mean area under the serum concentration-time curve decreased significantly (P less than 0.001) after ciprofloxacin was taken with 200 mg ferrous fumarate. The relative bioavailability was 30% when ciprofloxacin was given with ferrous fumarate. The maximum blood level decreased from 2.1 +/- 0.9 (control) to 0.6 +/- 0.2 mg/l (with ferrous fumarate). Further studies are needed to determine if chronic treatment with ferrous fumarate further decreases the relative bioavailability. For the moment administration of ciprofloxacin with ferrous fumarate should therefore be avoided.

A simple high pressure liquid chromatographic method for the determination of fluorouracil to monitor patients on regional infusion for hepatic metastases

A rapid and sensitive high pressure liquid chromatographic method has been developed for the routine monitoring in serum of the antineoplastic agent fluorouracil, during continuous intraportal administration. Serum spiked with internal standard, bromouracil, was gently shaken for 10 min with ethylacetate at an acidic pH. The evaporated extract was dissolved in the mobile phase containing potassium phosphate buffer. Assays were performed at ambient temperature on a Chrompack LiChrosorb RP 18 column (2 X 100 X 3.0 mm) equipped with a guard column. The retention time of fluorouracil was 2-6 min. The calibration curve was linear from 25 to 2,000 ng/ml. The coefficient of variation was less than or equal to 1.6% for within-run precision and less than or equal to 2.9% for day-to-day precision. The mean recovery of fluorouracil was 57%.