Structure—activity relationships for enhancement of paracellular permeability by 2-alkoxy-3-alkylamidopropylphosphocholines across Caco-2 cell monolayers
作者:Dong-Zhou Liu、Susan L. Morris-Natschke、Louis S. Kucera、Khalid S. Ishaq、Dhiren R. Thakker
DOI:10.1021/js9900957
日期:1999.11
The oral route is the preferred route of delivery for a large number of drug molecules. However, the intestinal epithelium presents a formidable barrier for delivery of drugs into systemic circulation. Phospholipids are among compounds that enhance the absorption of drugs across the intestinal epithelium. In this paper, we describe structure-activity relationships for phospholipid derivatives as enhancers of paracellular permeability across Caco-2 cell monolayers. in a series of 2-alkoxy-3-alkylamidopropylphosphocholine derivatives, compounds with a long chain at C-3 (R-3) and short chain at C-2 (R-2) were potent in causing a decrease in transepithelial electrical resistance (TEER) and an increase in mannitol transport, but also showed significant cytotoxicity. Compounds with 9-11 carbons at C-3 and 6-10 carbons at C-2 provided good separation (up to 2.7-fold) between activity and cytotoxicity. Notably, a good correlation (r(2) = 0.93) was observed between EC50 (TEER) [concentration that caused a drop in TEER to 50% of its control (untreated) value] and EC10X (mannitol) [concentration that caused 10-fold increase in mannitol transport over the control (untreated) value], confirming that a decrease in TEER is associated with enhanced permeability of the hydrophilic compounds across Caco-2 cell monolayers. Compounds with medium to long carbon chains at C-2 and C-3, and the total carbons in the alkyl chains > 20, showed poor activity and no cytotoxicity.