Question

What should be the log P value for an ideal drug candidate for transdermal permeation:

• A. Below 1
• B. 1-3
• C. 5-7
• D. Above 7

Hint:

For transdermal drugs, a log P value of 1-3 ensures optimal permeation through the lipid-rich skin barrier while maintaining systemic bioavailability.

Answer 1

The Correct Option is B

Step 1: Understanding log P value. The log P value is a measure of a drug's lipophilicity, representing its distribution between a lipid (oil) phase and an aqueous phase. It determines how easily a drug can permeate lipid membranes, such as the skin. 

Step 2: Log P value range for transdermal permeation. For transdermal delivery, the drug must have balanced hydrophilic and lipophilic properties: - A log P value of 1-3 is ideal, ensuring sufficient lipid solubility for permeating the skin's lipid barrier while maintaining water solubility for systemic absorption. 

Step 3: Why other options are incorrect. 
- (A) Below 1: Too hydrophilic, making it difficult to cross the lipid-rich stratum corneum. 
- (C) 5-7: Too lipophilic, leading to accumulation in the skin and poor systemic absorption. 
- (D) Above 7: Extremely lipophilic, making it almost impossible to achieve systemic delivery.