Backgrounds: Ion-exchange fibers are functional polymer materials with hydrophobic polymer chains and ion-exchange groups connected to the non-cross-linked grafted side chains.The ion-exchange is a stoichiometric process in which any counter-ions that leave the ion-exchange groups are replaced by an equivalent amount of other counter-ions.This is a consequence of the electro neutrality requirement.Objective: During the fibers loading procedure, the polymorph of the drug was destroyed.Drug molecules rearrange according to the sequence of ion-exchange groups.It is conjectured that using drug-loaded fiber can completely eliminate any problems with polymorphism.The aim of this study is to investigate if the ion-exchange fibers can eliminate the dissolution variance introduced by polymorphism.Methods: Cimetidine in different crystal forms were obtained by recrystallization method.The polymorph was identified by melting point, DSC, microscopy and powder X-ray diffraction.The confirmed cimetidine was loaded onto the ion-exchange fiber.Then the drug-loaded fiber and simple cimetidine bulk were compressed into tablets respectively using the same prescription.The dissolution tests were executed under certain conditions to compare the release characteristics of drug-loaded fiber and simple drug tablets.Results: The obtained cimetidine was confirmed to be in the A and B crystal form by melting point, DSC, microscopy and powder X-ray diffraction.When in the condition of 50r/min, 37℃ and 500ml medium (0.01M HC1 or PBS6.8), the dissolution profiles of A and B crystal form cimetidine tablets had a significant difference, however, in the situation of drug-loaded fiber the dissolution files were almost the same.Compared to the simple cimetidine tablets, cimetidine-loaded fiber tablets had sustained release characteristic.Conclusions: Results showed that ion-exchange fiber could eliminate the impact of polymorphism on drug dissolution.Loading drug onto the fiber could be an effective solution to polymorphism problems that should be considered along with traditional methods.The characteristics of drug release from the fiber are independent of the crystal form used to make it; it can even be a mixer, which definitely saves the recrystallization step.Unlike the traditional methods, drugs loaded on the fiber will always be physically stable until being released by the body fluid ions, which ensures the drug stability during the production and storage and guarantees the safety during clinical use.In addition, drug-loaded fiber also has the function of sustained release.