¹Faculty of Pharmacy, Department of Pharmaceutical Technology, Marmara University, 34668 Haydarpaşa, Istanbul, Turkey DOI : 10.12991/mpj.20151910464 Betahistine has been used in the treatment of diseases accompanied by impaired peripheral circulation, e.g. Ménière"s syndrome, to reduce the frequency of episodes of vertigo and tinnitus. The drug has a short half-life and should be taken three times daily. Its contraindication in patients with peptic ulcer history and the difficulty of frequently dosing requires administration ways other than the oral route. The aim of this study was to prepare transdermal therapeutic system formulations containing betahistine by using synthetic and FDA approved polymers, Eudragit RL 100 and Eudragit RS 100. All the ingredients were evaluated for their excipient-drug compatibility, using Differantial Scanning Calorimetry (DSC) tests. Formulations with different excipient ratios were prepared and evaluated for their macroscopic properties (general appearance, homogeneity, flexibility, transparency and color). Results indicated that there was no incompatibility between drug and excipients. Excipient ratios were optimised according to the macroscopic properties of the formulations. Keywords : Betahistine, transdermal therapeutic system, DSC, Eudragit