_____ products deliver drugs through the skin into the systemic circulation for percutaneous absorption.

• A. Transdermal
• B. Topical
• C. Transcutaneous
• D. Dermal

Answer: (A)

Percutaneous absorption into systemic circulation is achieved by transdermal delivery. This term specifically denotes delivering drug through the skin so it enters the bloodstream and produces systemic effects, as seen with nicotine or fentanyl patches. Topical products are meant for local action on the skin and aren’t designed to achieve consistent systemic levels. Transcutaneous is not the standard term used to describe products intended for systemic skin absorption, and dermal typically refers to the skin itself or local skin effects rather than systemic delivery. Transdermal systems are often designed with a rate-controlling mechanism to provide steady plasma levels and can bypass first-pass metabolism, which is a key advantage of this route.