Lecture 13: Transdermal drug delivery in CV Flashcards

1
Q

What are the three layers of the skin?

A
  1. Epidermis
  2. Dermis
  3. Subcutaneous tissue
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2
Q

What cells are found in the epidermis?

A
  • Keratinocytes
  • Melanocytes
  • Langerhans cells
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3
Q

What is found in the dermis layer? (5)

A
  • Sweat duct
  • Sebaceous gland
  • Sweat gland
  • Arrector pili
  • Hair follicle
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4
Q

What is found in the subcateneous tissue?

A
  • Blood vessels
  • Fat lobules
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5
Q

What is the principle barrier of the skin?

A

Stratum corneum

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6
Q

What is the largest organ of the body?

A

Skin

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7
Q

What is the size of the skin?

A

1.8m2

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8
Q

What is the pH of the skin surface

A

pH 5

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9
Q

What are the routes transdermal drugs use?

A
  1. Shunt route
  2. Trancellular route
  3. Intracellular route
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10
Q

What are the physiochemical properties affecting transdermal drug delivery?

A
  • Ability to cross lipid bilayer, especially corneocytes
  • Diffusion through aqueous environment, epidermis
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11
Q

What are the general properties required for transdermal drug delivery?

A
  • Molecular weight < 500
  • LogP in the range of 1 to 4
  • Maximum daily dose of 10mg/ day
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12
Q

Give examples of drugs delivered transdermally (3)

A
  • Estradiol
  • Fentanyl
  • Nicotine
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13
Q

What is ficks law of diffusion?

A

Flux of drug molecules from high to low concentration

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14
Q

What are the five principles of skin permeation?

A
  1. Selection of suitable drug molecule
  2. Release of drug from formulation
  3. Use thermodynamics
  4. Alcohol can help - partitions into skin, sets up a transient reservoir for drug to partition into, drives maximum thermodynamic activity
  5. Occlusion increases delivery of most drugs - Hydrates skin by blocking transdermal water loss, EMLA cream applied under occlusive dressing
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15
Q

How is skin permeation measured?

A

Using franz diffusion cell

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16
Q

What are the advantages of transdermal patches?

A
  • Avoids the harsh environment of the GI tract
  • Drug reaches systemic circulation whilst avoiding 1st pass metabolism
  • Patches can be easily and quickly removed
  • High potent compliance
17
Q

What are the advantages of transdermal patches?

A
  • Avoids the harsh environment of the GI tract
  • Drug reaches systemic circulation whilst avoiding 1st pass metabolism
  • Patches can be easily and quickly removed
  • High potent compliance
18
Q

What are the limitations of transdermal patches?

A
  • Low dose of drug
  • Drug needs to meet specific physiochemical criteria for delivery
19
Q

Name the approved transdermal patches? (9)

A
  • Scopolamine
  • Nicotine
  • Estradiol
  • Fentanyl
  • Buprenorphine
  • Testosterone
  • Glyceryl nitrate
  • Methylphenidate
  • Selegiline MOI
20
Q

What is scopolamine for?

A

Motion sickness

21
Q

What is nicotine for?

A

Smoking cessation

22
Q

What is estradiol used for?

23
Q

What is fentanyl used for?

A

Chronic pain

24
Q

What is buprenorphine used for?

A

Chronic pain

25
What is glyceryl nitrate used for?
Angina
26
What is methylphenidate used for?
ADHD
27
What is selegiline MOI used for?
Parkinsons disease
28
What are the three different types of patches?
1. Simple drug in adhesive patch 2. Drug in matrix patch 3. Rate limiting membrane type patch