H. Ellens et al., IN-VITRO PERMEABILITY SCREENING FOR IDENTIFICATION OF ORALLY BIOAVAILABLE ENDOTHELIN RECEPTOR ANTAGONISTS, Advanced drug delivery reviews, 23(1-3), 1997, pp. 99-109
In vitro intestinal permeability screening identified a compound, SB 2
17242, in the indane carboxylic acid series of endothelin receptor ant
agonists, with greatly improved permeability over the initial lead com
pound in this series. Based on mucosal-to-serosal and serosal-to-mucos
al permeability studies, and on the fact that SB 217242 transport does
not correlate with changes in mannitol permeability, it was concluded
that SB 217242 follows a passive transcellular pathway. Permeability
studies at different pH values demonstrate that the permeating species
is the unionized form of SB 217242. This compound is well absorbed up
on intraduodenal dosing in the rat (Ohlstein et al. (1996) J. Pharm. E
xp. Ther. 276, 609-615).