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Updated: Jun 10, 2026

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Coexistence of passive and carrier-mediated processes in drug transport
Kiyohiko Sugano1, Manfred Kansy, Per Artursson
1Pfizer, Research Formulation, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, UK. kiyohiko.sugano@pfizer.com
Abstract:
The permeability of biological membranes is one of the most important determinants of the pharmacokinetic processes of a drug. Although it is often accepted that many drug substances are transported across biological membranes by passive transcellular diffusion, a recent hypothesis speculated that carrier-mediated mechanisms might account for the majority of membrane drug transport processes in biological systems. Based on evidence of the physicochemical characteristics and of in vitro and in vivo findings for marketed drugs, as well as results from real-life discovery and development projects, we present the view that both passive transcellular processes and carrier-mediated processes coexist and contribute to drug transport activities across biological membranes.
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