Abstract Manuscript received: December 2014 The purpose of this study was to evaluate the in vitro release kinetics of Na3CaDTPA, a well-known and widely-used decorporation agent, from a topical microemulsion-gel formulation in comparison with a conventional gel. For the preparation of hydrogels, Carbopol 934 polymer was used. Release studies were conducted using both hydrophobic (polycarbonate) and hydrophilic (mixed cellulose esters) membranes.