Which term describes medication designed to pass through the skin?

• A. Toxic
• B. Syndrome
• C. Transdermal
• D. Urinate

Answer: (C)

Transdermal delivery describes medications designed to pass through the skin and into the bloodstream, often via a patch that releases drug gradually. This route aims for systemic effects, not just local action on the skin, by taking advantage of drugs formulated to penetrate the skin barrier. The skin’s outer layer, the stratum corneum, is a major barrier, so effective transdermal drugs are typically small and lipophilic enough to diffuse into dermal vessels. The other terms don’t describe how a drug enters the body: toxic means harmful, syndrome is a set of signs and symptoms, and urinate refers to excretion in urine.