PharmacyLesson 4 of 4 in the course Routes of drug administration

Skin Barriers and Delivery Routes in Transdermal Drug Administration

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Transdermal drug delivery moves an active ingredient across the skin so that it can enter the circulation and produce a systemic effect. Patches and ointments are familiar examples. This lesson explains why the skin is a challenging barrier, how drugs can cross it, and how delivery devices can help.

The skin protects the body from external substances and microorganisms and helps prevent loss of body fluids. These essential functions also make it difficult for medicines to pass through.

All flashcards

What is transdermal drug delivery?
Administration in which an active ingredient crosses the skin to enter circulation and produce a systemic effect.
Why does the stratum corneum resist drug diffusion?
Its dead, flattened keratinocytes are surrounded by a lipid matrix that forms a substantial diffusion barrier.
How do transcellular and intercellular transport differ?
Transcellular transport passes through skin cells and their membranes; intercellular transport follows spaces between cells.
What role does dermal microcirculation play in transdermal delivery?
Small dermal vessels can carry absorbed drugs into systemic circulation and contribute to temperature regulation.
How can microneedles assist transdermal delivery?
They create microchannels through the stratum corneum, helping compounds cross the outer skin barrier.

Quiz questions

  1. Which skin layer is the principal barrier to transdermal drug diffusion?Answer: The stratum corneum
  2. Why does diffusion occur faster through the viable epidermis than through the stratum corneum?Answer: Its living cells contain more water.
  3. Which sequence describes the transcellular route across the stratum corneum?Answer: The drug crosses cell membranes and cell contents repeatedly.
  4. What can appropriate solubilization of an active ingredient do for intercellular delivery?Answer: It can enhance delivery and broaden the range of compounds delivered.
  5. How can microneedles help both lipophilic and hydrophilic compounds cross the skin?Answer: They create microchannels through the outer skin barrier.

Based on the Wikipedia article Transdermal, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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