Abstract
In order to clarify the interactions between drugs and natural polymer supplements, the binding tendency of warfarin, ketoprofen and chlorpromazine with six kinds of commonly used natural polymer supplements-low molecular weight alginate, chitosan, guar gum degradation products, wheat albumin, dietary fiber derived from beer yeast and indigestible dextrin-were investigated by means of ultra-filtration. Though each of the drugs bound to the supplements, the degree of the binding varied largely with the different combinations of the drugs and the supplements. Specifically, acidic drugs showed significant binding with chitosan, which was probably due to electrostatic interaction. Binding between chitosan and warfarin was found to be dose-dependent and binding between all of the drugs and chitosan was found to vary with the type of chitosan product. In this regard, among widely available products, some hardly bound to the drugs at all whereas others bound very easily. These results suggest that the absorption of drugs could be inhibited when natural polymer supplements are taken simultaneously. Therefore, patients taking physiologically active drugs such as warfarin or TDM drugs should be instructed to avoid polymer supplements.
