RESUMO
The feasibility of transdermal controlled delivery system of 17beta-estradiol was investigated by conducting in vitro release studies. Several new 17beta-estradiol unilaminate adhesive devices capable of releasing 17beta-estradiol in a controlled fashion over a 24-h, 36-h, 96-h, 104-h, 168-h, and 216-h period have been developed using acrylic resins (Eudragits E100, RSPO, and RLPO) as adhesive and rate-controlling polymers. The in vitro release profiles of 17beta-estradiol from various TDS unilaminate devices were characterized in a new developed dissolution tester vessel (total volume 200 ml), using a new paddle. The release of drug from different formulations was measured by a sensitive high-performance liquid chromatographic (HPLC) method. The release of drug from all prepared adhesive devices seems to obey zero-order kinetics (r > 0.98). The effect of two different plasticizers (acetyltriburyl citrate [ATBC] and triethyl citrate [TEC]) on the release patterns of 17beta-estradiol from TDS formulations was studied, and they were almost identical. The effect of two different release modifiers, propylene glycol (PG) and myristic acid (MA), on the release pattern of 17beta-estradiol from prepared unilaminate devices was evaluated. It was shown that the use of these release modifiers significantly increased the release of 17beta-estradiol from a TDS unilaminate patch. Furthermore, these data clearly demonstrated that the acrylic resins are suitable polymers for the preparation of 17beta-estradiol TDS adhesive devices.
