PERCUTANEOUS PASSAGE OF DRUGS - TRANSDERM AL DELIVERY SYSTEMS

The ten-fold increase in the number of commercially-available transder mal delivery devices (TDDs) over the last ten years attests to the app eal of this approach. TDDs sidestep some of the drawbacks of oral admi nistration (e.g., breakdown by gastrointestinal enzymes and a hepatic first-pass effect) and, similar to intravenous infusions, ensure const ant-rate delivery of active ingredients to the bloodstream, providing stable plasma drug levels over at least 24 hours. TDDs may be particul arly valuable for improving compliance in patients with chronic diseas es. The various types of TDD are reviewed in this article.