Transdermal drug delivery: Past, present, future trends

Drug therapy is a process for cure the patient diseases. And in this study several studies can involve such as Photodynamic therapy (PDT), Music therapy, and Chewing gum as drug delivery system. Photodynamic therapy is a relatively new procedure used for the treatment of acne. Music has frequently been used as a therapeutic agent from the ancient times. The concept of Music Therapy is dependent on correct intonation and right use of the basic elements of music. Chewing gum is an obvious drug delivery system for local treatment of diseases in the oral cavity and in the throat, as sustaining the release of active substances may deliberately prolong exposure. Key-Words: Photodynamic therapy (PDT), Music therapy, Chewing gum therapy, Cancer, Photosensitizing agent Introduction Delivering medicine to the general circulation through the skin is seen as a desirable alternative to taking it by mouth. Patients often forget to take their medicine, and even the most faithfully compliant get tired of swallowing pills, especially if they must take several each day. Additionally, bypassing the gastrointestinal (GI) tract would obviate the GI irritation that frequently occurs and avoid partial first-pass inactivation by the liver. Further, steady absorption of drug over hours or days is usually preferable to the blood level spikes and troughs produced by oral dosage forms. These advantages are offered by the currently marketed transdermal products. One of the most successful, the nicotine patch, releases nicotine over sixteen hours, continuously suppressing the smoker’s craving for a cigarette. The scopolamine patch is worn behind the ear and releases the alkaloid for three days, preventing motion sickness without the need to swallow tablets periodically. The fentanyl patch acts for seventy-two hours, providing long-lasting pain relief. And an estrogen–progestin contraceptive patch needs to be applied only once a week, a boon for women who find it onerous to take one pill every day. * Corresponding Author The transdermal route is indeed desirable, but there is one small obstacle: whereas the function of the GI tract is to render ingested material suitable for absorption, the skin’s function is to keep things out of the body. The major barrier within the skin is the stratum corneum, the top layer of the epidermis. The stratum corneum consists of keratinized, flattened remnants of once actively dividing epidermal cells. Hygroscopic, but impermeable to water, it behaves as a tough, flexible membrane. The intercellular space is rich in lipids. The stratum corneum is about ten microns thick, but on the palms and soles it ranges up to 600 microns in thickness. Permeation of drug across skin Characteristics of several drugs delivered transdermally Transdermal absorption occurs through a slow process of diffusion driven by the gradient between the high concentration in the delivery system and the zero concentration prevailing in the skin. Thus, the delivery system must be kept in continuous contact with the skin for a considerable time (hours to days). The major products currently marketed for transdermal absorption are the transdermal therapeutic systems (TTS), popularly known as patches. The functional parts of a patch, proceeding from the visible surface inward to the surface opposed to the skin are: • An impermeable backing. • A reservoir holding the active ingredient, together with release-controlling materials. Review Article [Gupta et al., 2(9): Sep., 2011]