Which term denotes a dosage form designed to deliver through the skin via a patch?

• A. Ointment
• B. Cream
• C. Rectal
• D. Transdermal

Answer: (D)

The central idea is recognizing a patch-based system designed to move drug through the skin into systemic circulation, which is called transdermal delivery. A patch implies a dosage form that adheres to the skin and releases the drug over time for systemic effect, not just local skin treatment. Ointments and creams are topical formulations intended mainly for surface or local action on the skin, though they may allow some absorption, they’re not defined by patch-based delivery. Rectal indicates a non-skin route of administration and does not involve a patch. Transdermal patches provide controlled, sustained release and can bypass first-pass metabolism, which is why transdermal is the best descriptor for a patch-delivered skin system.