Transthorakal
Transthorakal, a term derived from the German words for "through the skin," refers to the administration of medications via transdermal routes. This method delivers active pharmaceutical ingredients directly through the epidermis, allowing for controlled, systemic absorption over extended periods. The concept emerged in the 1970s with the development of the first transdermal patch for nicotine replacement therapy, aimed at reducing the severity of nicotine withdrawal symptoms and easing smoking cessation. Subsequent breakthroughs included patches for hormone replacement therapy and analgesia in chronic pain conditions.
Mechanistically, a transthorakal system comprises a drug reservoir, a permeation-enhancing vehicle, and an adhesive layer. The
Clinical advantages of transthorakal delivery include stable plasma concentrations, avoidance of first‑pass hepatic metabolism, reduced gastrointestinal
Regulatory agencies such as the FDA and EMA have approved dozens of transthorakal products, ranging from analgesics,