Abstract: Transdermal drug delivery is probably the most innovative way of drug delivery since it avoids problems such as gastrointestinal irritation, hepatic first-pass metabolism and variation in delivery rates. It is also suitable for unconscious patients. The technology of transdermal delivery has been in use for over 25 years and had generated tremendous interest amongst drug delivery companies in the early 1980's. However, the success of transdermal drug delivery has been severely limited by the inability of most drugs including large drug molecules to enter the skin at therapeutically useful concentrations because of the poor permeability of stratum corneum. Recently, active transdermal delivery in increasing skin permeation has been shown to dramatically increase drug transport. The promise of active transport mechanisms has brought back interest to deliver many more molecules into the skin for a wide range of possible therapeutic applications.
In 1979, the US Food and drug Administration (FDA) approved the first transdermal product Transdermal Scop (Ciba, now Novartis) containing scopolamine for prevention of nausea, vomiting of motion sickness. This transdermal system provided a novel form of controlled drug delivery and was a therapeutic breakthrough. It facilitated passage of required dose and then continuous passage of the drug through the pores of the skin into systemic circulation. The patients have to attach a patch, the corner stone of this drug delivery device, onto skin like an adhesive bandage and do nothing except replace it every three days. Transdermal Scop for instance. The transdermal drug delivery marked the beginning of the advanced era of non-invasive systemic drug delivery.