Transdermal
systems

With a transdermal system, active drugs are applied via a patch, which enables more effective and better tolerated absorption (that is, the incorporation of the therapeutic agent into the bloodstream).

Therapeutic systems release the active ingredient particularly slowly and in a controlled manner over a long period of time. The active ingredients diffuse through the skin and enter the bloodstream directly via blood vessels close to the skin, without passing through the gastrointestinal tract or the liver.

There are various systems for releasing an active ingredient from the patch into the skin. These can be divided into four categories: passive diffusion, energy-driven diffusion, mechanical perforation, and energy-driven perforation. Transdermal patches with a drug matrix (matrix patch) allow passive diffusion and dominate the market for transdermal systems.

The main therapeutic advantages of transdermal systems over other dosage methods are:

• Decreased application frequency
• Constant drug levels
• Reduced adverse effects
• Improved drug intake compliance
• Increased bioavailability
• Improved pharmacokinetics