Transdermaalit

Transdermaalit refers to transdermal delivery systems, a method of administering drugs through the skin to achieve systemic therapy. These systems are designed to provide controlled release over hours or days and rely on diffusion across the skin’s outer barrier, the stratum corneum.

A typical transdermal system consists of a backing layer, an adhesive that contains the active drug, and often a rate-controlling element. In reservoir patches, the drug is housed in a separate layer; in matrix patches, the drug is dispersed within the adhesive itself. The release rate and thus the amount absorbed depend on the drug’s properties (notably lipophilicity and molecular size), the formulation, and the condition of the wearer’s skin.

Mechanism of action involves the gradual diffusion of the drug from the patch through the epidermis and dermis into the bloodstream, aiming for a steady-state plasma concentration. The approach can reduce peaks and troughs seen with oral dosing and avoids first-pass metabolism in the liver.

Applications include nicotine patches for smoking cessation, fentanyl and buprenorphine patches for pain management, and estrogen or testosterone patches for hormone replacement therapy. Lidocaine patches provide localized analgesia. Research spans vaccines and other therapeutics, as well as advanced methods like microneedle and iontophoresis-based systems.

Advantages include improved adherence, stable drug levels, and avoidance of gastrointestinal issues. Limitations comprise potential skin irritation or dermatitis, variability in absorption due to skin condition, and reduced suitability for drugs with unsuitable molecular properties. Safety considerations cover proper labeling, site rotation, and removal before procedures where patches pose a hazard.