Artificial membrane assays to assess permeability.

This paper reviews the development of artificial membrane assays in the last decade. Reasons why parallel artificial membrane assays (PAMPA) became widely used are discussed and the various PAMPA assays targeting gastro-intestinal absorption, blood brain barrier and skin penetration are presented. Improvements in the assay technology like the introduction of a paracellular component and the critical factors to get quality data are reviewed. The question how does PAMPA compare with Caco-2 monolayer permeability is being addressed. New dimensions in artificial membrane assays like octanol/water logP measurement, influence of excipients on solubility/permeability and binding constants measurements are introduced. Finally, similarity and differences between partition coefficients and permeability values are discussed.