Kinetic modelling of passive transport and active efflux of a fluoroquinolone across Caco-2 cells using a compartmental approach in NONMEM

Abstract

The purpose was to develop a general mathematical model for estimating passive permeability and efflux transport parameters from in vitro cell culture experiments. The procedure is applicable for linear and non-linear transport of drug with time, <10 or >10% of drug transport, negligible or relevant back flow, and would allow the adequate correction in the case of relevant mass balance problems. A compartmental kinetic approach was used and the transport barriers were described quantitatively in terms of apical and basolateral clearances. The method can be applied when sink conditions are not achieved and it allows the evaluation of the location of the transporter and its binding site. In this work it was possible to demonstrate, from a functional point of view, the higher efflux capacity of the TC7 clone and to identify the apical membrane as the main resistance for the xenobiotic transport. This methodology can be extremely useful as a complementary tool for molecular biology approaches in order to establish meaningful hypotheses about transport mechanisms.

Kewords: :

• Absorption kinetics
• efflux mechanisms
• Caco-2
• P-glycoprotein
• fluoroquinolones
• mathematical modelling

Acknowledgements

The study was partly supported by SAF-96-1710 and GV-99-99-1-12 from Ministerio de Educación y Ciencia (MEC) and Generalidad Valenciana, respectively. The modelling analysis constitutes part of Workpackage 15 of the Biosim Project funded by the European Commission (LSHB-CT-2004-005137). A. Ruiz-García was recipient of a grant from MEC. Joan Freixas provided the fluoroquinolone used (CENAVISA S.A., Reus, Spain). The authors acknowledge Pharsight Corporation for the Pharsight Academic License of Winnonlin 4.1.