ABSTRACT
Skin is an optimal interface for systemic drug administration. Transdermal drug delivery (TDD) is the controlled release of drugs through intact and/or altered skin to obtain therapeutic levels systematically and to affect specified targets for the purpose of, for example, blood pressure control, pain management, and others. Dermal drug delivery (DDD) is similar to TDD except that the specified target is the skin itself (1). TDD has the advantages of bypassing gastrointestinal incompatibility and hepatic “first pass” effect; reduction of side effects due to the optimization of the blood concentration time profile; predictable and extended duration of activity; patient-activated/patient-modulated delivery; elimination of multiple dosing schedules, thus enhancing patient compliance; minimization of inter-and intrapatient variability; reversibility of drug delivery allowing the removal of drug source; and relatively large area of application compared with the mucosal surfaces (1).
