In vitro drug permeation enhancement potential of aloe gel materials.

Aloe vera gel previously showed the ability to increase the bioavailability of vitamins and to enhance the in vitro transport of a macromolecular drug across intestinal epithelial cell monolayers. The purpose of this study is to investigate the potential of other species of aloe to act as drug absorption enhancement agents. The effect of gel materials from three South African aloes; Aloe ferox, A. marlothii and A. speciosa on the transepithelial electrical resistance and permeability of atenolol across excised intestinal tissue of the rat as well as the transport of FITC-dextran across Caco-2 cell monolayers was investigated. The aloe gel materials exhibited the ability to statistically significantly reduce the transepithelial electrical resistance of excised rat intestinal tissue but did not significantly increase the transport of atenolol across this in vitro tissue model at the concentrations tested. At least one concentration of each aloe gel material enhanced the transport of FITC-dextran statistically significantly across Caco-2 cell monolayers. The aloe gel materials showed potential to act as drug absorption enhancing agents across intestinal epithelia. The absorption enhancement effect was dependent on the type of in vitro model and type of drug was investigated.