Predicting the human jejunal permeability and fraction absorbed of fluoroquinolones based on a biophysical model.

The purpose of this study is to predict human jejunal permeability (P(eff)) and fraction absorbed in human (%F(a)) for a group of antibacterial fluoroquinolones (FQs), by using a biophysical model based on measured Caco-2 permeability. The predicted P(eff) (in 10(-4) cm · s(-1) units) ranged from 0.7 (norfloxacin) to 4.5 (pefloxacin). The calculated %F(a) for norfloxacin = 51% (lit. 35%) and for ciprofloxacin = 76% (lit. 81%). Most of the FQs showed calculated %F(a)>90%, and are expected to be well-absorbed. Estimates of P(eff) can be predicted by the biophysical model. From these values, the human absorption may be calculated. Where absorption comparisons were possible, the agreement was acceptably good.