Vol. 290, Issue 3, 1212-1221, September 1999

A Conditionally Immortalized Epithelial Cell Line for Studies of Intestinal Drug Transport¹

Staffan Tavelin², Vladan Milovic^{2 3}, Göran Ocklind, Susanne Olsson and Per Artursson

Department of Pharmacy, Division of Pharmaceutics, Uppsala University, Uppsala, Sweden

A new cell culture model that better mimics the permeability of the human small intestine was developed for studies of passive drug transport. The intestinal epithelial cell line, 2/4/A1, conditionally immortalized with a temperature-sensitive mutant of the growth-promoting oncogene simian virus 40 (SV40) large T, was grown on permeable supports. The cells grew at 33°C, where the oncogene is fully active, but stopped growing and entered a differentiation program at 39°C, where the oncogene is inactive. Significant cell death was observed at 39°C and, therefore, growth conditions under which 2/4/A1 cells survive during the differentiation process were developed. Cells grown on extracellular matrices which contained laminin at an intermediate temperature of 37°C formed viable differentiated monolayers with tight junctions, an increased expression of brush border enzymes, and a paracellular permeability that was comparable to that of the human small intestine. The permeability of 17 structurally diverse drugs gave a sigmoidal relationship with the absorbed fraction of the drugs after oral administration to humans. The relationship was compared with those obtained with the well established Caco-2 model and after in vivo perfusion of the human jejunum. The transport of drugs with low permeability in 2/4/A1 monolayers was comparable to that in the human jejunum, and up to 300 times faster than that in Caco-2 monolayers. The transport of drugs with high permeability was comparable in all models. These results indicate that 2/4/A1 monolayers are promising alternatives to Caco-2 monolayers for studies of passive drug transport.