The Effect of Sodium Ferrous Citrate on Ciprofloxacin Absorption

Abstract

The effect of sodium ferrous citrate (SFC) on the relative bioavailability of ciprofloxacin (CPFX) after a single 600-mg oral dose of CPFX was studied in three healthy volunteers. Blood samples were collected at regular intervals 0-8 h post-dose. CPFX concentrations in serum were determined by bioassay method. The area under the serum concentration-time curve (AUC) decreased significantly (p<0.05) after CPFX was taken with 100 mg SFC. The relative bioavailability was 33.1±15.0% when CPFX was given with SFC. The maximum blood level decreased from 3.96±1.30 (control) to 1.36±1.00μg/ml (with SFC). The mechanism of the CPFX-iron ion interaction appears to be the formation of chelation complex.
Ascorbic acid is known to interfere with the formation of chelation complex. Therefore, the effect of SFC on the absorption of CPFX with concomitant administration of 1500 mg ascorbic acid was studied in two healthy volunteers using the same method. The AUC increased from 4.37 and 3.50 (with SFC) to 5.23 and 5.39μg·hr/ml (with SFC and ascorbic acid). However, the relative bioavailability was 33.3 and 27.7% when CPFX was taken alone. Ascorbic acid did not appear to interfere much with the formation of CPFX-iron ion chelation complex.