Intestinal absorption of a series of 6-fluoquinolone derivatives: a comparative study

The intestinal absorption rate constants of the five 6-fluoquinolones (norfloxacin, ciprofloxacin, pefloxacin, CNV 8802 and CNV 8804), have been estimated in the rat (n = 5) by means of an "in situ" intestinal perfusion method. Remaining 6-fluoquinol one concentrations in the perfusion liquid at fixed time (15, 30, 45, 60, 75, 90 and 120 minutes) were determined using a HPLC procedure with UV detection. Absorptions rate constants were estimated according to first order kinetics. A simple non-linear correlation between Ka and log K' on the one hand and a multiple linear correlation between Ka and the structural theoretical parameters: molar volume, dipolar moment and the charge associated to nitrogen 18 on the other, were performed. Only a correlation between Ka values as dependent variable versus dipolar moment and molecular volume values has been obtained, but this correlation is not statistically significant (p = 0.1808) and not accurate enough to have predictive value.