Topical absorption is influenced by tissue perfusion. Which statement is true?

Topical absorption is influenced by tissue perfusion. Which statement is true?

• A. Absorption is higher in poorly perfused tissue
• B. Absorption is lower in poorly perfused tissue
• C. Absorption is unaffected by perfusion
• D. Absorption is unpredictable regardless of perfusion

Answer: (B)

Topical absorption relies on a drug diffusing from the skin into the surrounding tissue and then into blood vessels. A key factor is tissue perfusion because blood flow acts as a sink that removes drug from the absorption site. When perfusion is high, the rapid removal of drug into the bloodstream maintains a strong concentration gradient, drawing more drug across the skin and into systemic circulation. Conversely, in poorly perfused tissue, there’s less removal of drug at the absorption site, the gradient isn’t maintained as effectively, and diffusion into the capillaries is reduced. So absorption is lower in poorly perfused tissue. This aligns with the idea that areas with good blood flow tend to have greater systemic absorption, while ischemic or poorly perfused areas show diminished absorption.

Topical absorption relies on a drug diffusing from the skin into the surrounding tissue and then into blood vessels. A key factor is tissue perfusion because blood flow acts as a sink that removes drug from the absorption site. When perfusion is high, the rapid removal of drug into the bloodstream maintains a strong concentration gradient, drawing more drug across the skin and into systemic circulation. Conversely, in poorly perfused tissue, there’s less removal of drug at the absorption site, the gradient isn’t maintained as effectively, and diffusion into the capillaries is reduced. So absorption is lower in poorly perfused tissue. This aligns with the idea that areas with good blood flow tend to have greater systemic absorption, while ischemic or poorly perfused areas show diminished absorption.