Importance of bile acids for novel oral absorption system containing polyamines to improve intestinal absorption

The synergetic improving effect of bile acids with spermine (SPM), a major polyamine, on the absorption of rebamipide, a poorly soluble and poorly absorbable drug (BCS Class IV), was evaluated in rats and beagle dogs. Although the absorption of rebamipide was improved by the addition of polyamines alone in normal rats, it was not improved in bile duct ligated (BDL) rats. The combinatorial use of sodium taurocholate (STC), a bile acid, with SPM improved the absorption of rebamipide even in BDL rats. In the beagle dogs, the oral administration of SPM alone did not enhance the absorption of rebamipide, but the combinatorial use of STC with SPM improved the absorption as well as in the BDL rats. These results indicate that bile acids are indispensable for the novel formulation containing SPM to improve the absorption of rebamipide after oral administration.