High permeability of the anionic form restricts accumulation of indomethacin by cultured gastric surface epithelial cells exposed to low apical pH.

The 'ion-trapping' hypothesis suggests that the intracellular concentration of acidic non-steroidal anti-inflammatory drugs in gastric epithelial cells could be much higher than in the gastric lumen, and that such accumulation could contribute to their gastrotoxicity. Our aim was to examine the effect of the pH of the apical medium on the apical to basal transfer of the acidic drug indomethacin (pKa 4.5) across a gastric mucous epithelial cell monolayer, and to determine whether indomethacin accumulated in cells exposed to a low apical pH.

A collagen IV matrix is required for guinea pig gastric epithelial cell monolayers to provide an optimal model of the stomach surface for biopharmaceutical screening.

The surface epithelial cells of the stomach represent a major component of the gastric barrier. A cell culture model of the gastric epithelial cell surface would prove useful for biopharmaceutical screening of new chemical entities and dosage forms. Primary cultures of guinea pig gastric mucous epithelial cells were grown on filter inserts (Transwells) for 3 days.