Background: Knowledge of the permeation characteristics of new chemical entities
across biological membranes is essential to drug research and development. Transport medium
composition may affect the absorption of compounds during in vitro drug transport testing. To preserve
the predictive values of screening tests, the possible influence of transport media on the solubility
of model drugs and on the activities of tight junctions and efflux transporter proteins (e.g., Pglycoprotein)
must be known.
Objective: The aim of this study was to compare the impact of different transport media on the bidirectional
transport of standard compounds, selected from the four classes of the Biopharmaceutical
Classification System (BCS), across excised pig intestinal tissue.
Methods: The Sweetana-Grass diffusion apparatus was used for transport studies. Krebs-Ringer bicarbonate
(KRB) buffer and simulated intestinal fluids in the fed (FeSSIF) and fasted (FaSSIF)
states were used as the three transport media, while the chosen compounds were abacavir (BCS
class 1), dapsone (BCS class 2), lamivudine (BCS class 3) and furosemide (BCS class 4).
Results: Abacavir exhibited lower permeability in both the simulated intestinal fluids than in the
KRB buffer. Dapsone showed similar permeability in all media. Lamivudine exhibited lower
permeability in FaSSIF than in the other two media. Furosemide exhibited improved transport with
pronounced efflux in FaSSIF.
Conclusion: Different permeation behaviors were observed for the selected drugs in the respective
media, which may have resulted from their different physico-chemical properties, as well as from
the effects that dissimilar transport media components had on excised pig intestinal tissue.