A conditionally immortalized epithelial cell line for studies of intestinal drug transport.

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 degrees C, where the oncogene is fully active, but stopped growing and entered a differentiation program at 39 degrees C, where the oncogene is inactive.

Chitosans as absorption enhancers of poorly absorbable drugs. 3: Influence of mucus on absorption enhancement.

Chitosans are potent nontoxic absorption enhancers after nasal administration but their effects on the intestinal epithelium in vivo has not been studied in detail. In this study, the effects of chitosans with varying molecular weights and degrees of acetylation on the absorption of a poorly absorbed model drug (atenolol) were studied in intestinal epithelial cell layers with or without a mucus layer and in an in situ perfusion model of rat ileum. The effects of the chitosans on epithelial morphology and release of lactate dehydrogenase (LDH) into the perfusate were investigated in the in situ model.

Freeze-thaw immobilization of liposomes in chromatographic gel beads: evaluation by confocal microscopy and effects of freezing rate.

Biological membranes immobilized in chromatographic gel beads constitute a multifunctional affinity matrix. Membrane protein-solute interactions and drug partitioning into the lipid bilayers can conveniently be studied. By the use of confocal laser-scanning microscopy (CLSM) the distribution of immobilized model membranes in the beads has been visualized for the first time.