Transdermal delivery involves the passage of therapeutic quantities of drug substances through the skin and into the general circulation for systemic effects. For transdermal drug delivery, it is considered ideal for the drug to migrate through the skin to the underlying blood supply without buildup in the dermal layers.
Transdermal delivery of drugs is effective and used to treat many different conditions. Transdermal drug delivery can be “individualized” for each patient by changing the drugs used, their concentrations, and the formulation. This type of drug delivery is routinely used for delivery of hormones, pain medication, nonsteroidal anti-inflammatory drugs (NSAIDs), antinauseant medications, and many others.
Transdermal delivery may have different advantages over other delivery systems, including:
- Avoids gastrointestinal (GI) drug absorption difficulties caused by GI pH, enzymatic activity and drug interactions with food, drink, and other orally administered drugs.
- A substitute for other routes of administration (e.g. oral administration, intravenous injection) when that route is unsuitable, as with vomiting, swallowing problems, resistant children and diarrhea.
- Avoids the first-pass effect, possibly avoiding the deactivation by digestive and liver enzymes.
- Patient acceptability. Transdermal delivery is noninvasive, avoiding the inconvenience of parenteral therapy.
- Ability to dissolve a wide range of medications with different chemical properties, making combination therapy with one transdermal cream possible.
- Provides extended therapy with a single application, improving compliance.
- Drug therapy may be terminated rapidly by removal of the application from the skin surface.1
For more information about transdermal delivery systems and their advantages, please read the article “Transdermals: the skin as part of a drug delivery system” by Allen, L.V. Jr.*
* Allen LV Jr. Transdermals: the skin as part of a drug delivery system. International Journal of Pharmaceutical compounding. 2011; 15(4): p. 308-315.