Question

Transdermal preparations are prepared for those drugs which

• A. Undergoes first pass metabolism
• B. have bigger molecules
• C. are costly
• D. are hydrophilic

Hint:

Transdermal candidates usually follow the "Rule of 5" for absorption: small molecule, lipophilic, and potent.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The main purpose of the transdermal route is to deliver drugs systemically while bypassing the gastrointestinal tract and liver.

Step 2: Detailed Explanation:
Oral drugs often suffer from extensive hepatic first-pass metabolism, which reduces their bioavailability.
By applying the drug through the skin, it enters the systemic circulation directly via capillaries, avoiding the initial pass through the liver.
For a drug to be suitable for transdermal delivery, it should be lipophilic, have a low molecular weight, and be potent to compensate for the limited surface area of application.

Step 3: Final Answer:
Transdermal delivery is preferred for drugs that undergo significant first-pass metabolism to improve overall bioavailability.