Monolayers of porcine alveolar epithelial cells in primary culture as an in vitro model for drug absorption studies

A Steimer, H Franke, E Haltner-Ukomado… - European journal of …, 2007 - Elsevier
A Steimer, H Franke, E Haltner-Ukomado, M Laue, C Ehrhardt, CM Lehr
European journal of pharmaceutics and biopharmaceutics, 2007Elsevier
Filter-grown monolayers of porcine alveolar epithelial cells (pAEpC) in primary culture have
been characterized as an in vitro model for pulmonary absorption screening of xenobiotics,
including substrates of efflux systems. Experimental conditions and a protocol for transport
experiments were optimized using transepithelial electrical resistances (TEER) and
permeability of marker compounds as acceptance criteria. Since new drugs often feature
poor water solubility, monolayer integrity in the presence of a solubilizer (dimethyl sulfoxide) …
Filter-grown monolayers of porcine alveolar epithelial cells (pAEpC) in primary culture have been characterized as an in vitro model for pulmonary absorption screening of xenobiotics, including substrates of efflux systems. Experimental conditions and a protocol for transport experiments were optimized using transepithelial electrical resistances (TEER) and permeability of marker compounds as acceptance criteria. Since new drugs often feature poor water solubility, monolayer integrity in the presence of a solubilizer (dimethyl sulfoxide) was tested. Transport studies were carried out with budesonide and triamcinolone acetonide, i.e., two drugs commonly administered to the lungs. Furthermore, expression of P-glycoprotein (P-gp) was assessed by immunofluorescence microscopy and transport studies employing the substrates rhodamine 123 and digoxin. Hydrocortisone-supplemented (0.5μg/ml) small airway basal medium as transport buffer and a maximal solubilizer concentration of 1.5% dimethyl sulfoxide were found to provide suitable conditions for drug transport studies across pAEpC, as reflected, e.g., by a minimum TEER of 600Ωcm2. Permeation of marker compounds was reproducible throughout several cell preparations and proved the model successful in distinguishing between low- and high-permeable drugs. P-gp expression was confirmed by immunocytochemistry, even though transport studies revealed no polarity in transepithelial marker transport. In conclusion, our results demonstrate that filter-grown monolayers of pAEpC can be used to study drug transport across alveolar epithelial barrier and thus, may represent a suitable in vitro model for pulmonary drug absorption and delivery.
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