Transdermal therapeutic systems and rate controlled drug delivery

One of the key design features of transdermal therapeutic systems, namely the system rate-control, and its impact on systemic therapy, are reviewed. Specifically, TTS(scopolamine) and TTS(estradiol) are evaluated as examples of the rate-controlled transdermal products. The use of these TTS products has resulted in controlled plasma concentration of drug and reduced side effects by the use of TTS(scopolamine) and more physiologic estradiol to estrone ratio with the transdermal dosage form of estradiol.