Transdermal drug delivery advantages

Describe the advantages and disadvantages of transdermal drug delivery over other routes of drag delivery. 

The relatively non-invasive nature of transdermal drug delivery, and the fact that this route can simultaneously avoid problems associated with presystemic metabolism and mimic (at least, to some extent) parenteral input profiles, are significant advantages. There have been, therefore, diverse attempts to exploit the skin for peptide and protein delivery. As we have noted before, transdermal administration, with or without one or more enhancement technologies, will always be limited to potent drugs and this accounts, once more, for the effort devoted to peptide and protein (i.e., typically very active substances) administration via this route. 

Transdermal drug delivery (TDD) is known to offer many advantages over the oral and injectable routes for systemic drug delivery. However, the skin is a complex and dynamic organ with marked barrier function, which results in limitations and variations in the amount and nature of drugs that can be delivered across the skin and into the bloodstream. Thus a continual search for ways to optimize the permeation of drugs across the skin exists, in an attempt to enhance delivery and improve patient compliance. 

---