Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHRM 829 Exam 3 > Topical > Flashcards

Topical Flashcards

1
Q

Stratum corneum

A
  • main barrier to permeation
  • the dead cells of the bricks are not permeable
  • permeation occurs by going through the lipid material (mortar) between the dead cells (bricks)

Function: lipid protective barrier

STATE OF HYDRATION IS DIRECTLY RELATED TO EASE OF PERMEATION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Living epidermis

A
  • living cells that do not contain capillaries
  • obtain nutrition by diffusion from dermis
  • source of skin color and tanning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Dermis

A
  • contains capillaries
  • DRUGS MUCH REACH THESE CAPILLARIES TO HAVE SYSTEMIC EFFECT
  • contains pain, thermal, and tactile sensors
  • must reach this layer to cause scarring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Hair Follicles & Sweat glands

A
  • secondary form of drug absorption that bypasses the stratum corneum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Functions of Skin

A

Containment
- confine the tissues and restrain the movement

Microbial Barrier
- pH is 5 which inhibits growth of bacteria

Chemical Barrier
- permeability resistance of stratum cornerum

Radiation Barrier
- exposure of UV stimulates melanin synthesis absorbing UV rays

Electrical Barrier
- high impedance to flow of electrical current
- must use salt solutions to overcome impedance

Thermal Barrier
- maintains 98.6 degree F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Topical Drug Delivery

A

local effects on barrier function

  • surface effect
  • stratum corneum effect
  • effects skin’s glands
  • effects on deep tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Transdermal Drug Delivery

A
  • systemic effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Topical Local Effects

A

Surface Effects
- zinc oxide for diaper rash
- sun block/sunscreen
- lip balm
- calamine lotion
- deodorant
- soap

Stratum corneum Effects
- emolliency: softening horny tissue
- keratolysis: chemical digestion and removal of horny tissue

Glands
- Antipersipriants: aluminum chloride
- Acne: soap, alcoholic solution, antibiotics, retinoids
- Hair remover (depilatory)

Deep Tissues
- corticosteroids
- NSAID (diclofenac)
- anesthetic (benzocaine)
- lighten pigmented skin (hydroquinone)
- skin cancer (5-fluorouracil)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ointments

A

Hydrocarbon Base (most hydrophobic)
- petrolatum
- polyethylene dissolved in mineral oil

Silicone Base (slightly hydrophobic)
- contains polydimethylsiloxane oil

Absorption Base
- ointment containing W/O emulsifiers

Water Soluble Base (most hydrophilic)
- polyethylene glycol ointment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Pastes

A

ointment into which a high concentration of insoluble particulate solid is added

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Creams

A

O/W or W/O emulsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gels

A

liquid phase trapped in matrix of natural or synthetic polymer (tragacanth, pectin, carrageenan, methylcellulose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Foams

A

air or gas emulsified liquid phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of drugs are we interested in transdermal delivery?

A
  • short systemic 1/2 life
  • extensive 1st pass metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Advantages of Transdermal

A
  • good compliance
  • constant delivery of drug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Components of Transdermal Patch

A

Backing membrane
Drug Reservoir
Rate Controlling membrane
Skin contact adhesive

17
Q

Requirements for Transdermal Drug

A
  • high skin permeability
  • low dose requirement (high potency)

Desire hydrophobic small drugs

18
Q

Types of Transdermal Patch

A

Membrane Modulated
- backing membrane
- drug reservoir
- rate controlling membrane
- adhesive

Adhesive Dispersion
- backing membrane
- drug reservoir
- rate controlling adhesive

Matrix Dispersion
- backing membrane
- drug + adhesive = matrix

19
Q

Active Ingredients in Patches

A

Clonidine (very small; not very hydrophobic)
estradiol/noregestromin
lidocaine
lidocaine + epinephrine
nicotine (very small; not very hydrophobic)
nitroglycerin (very small; not very hydrophobic)
estradiol (very small and hydrophobic)
oxybutynin
scopolamine
tesosterone
fentanyl (relatively small and hydrophobic)

Commonality: small and/or hydrophobic

20
Q

Example of Membrane Modulated

A

Nitroglycerin (227 Da)
- 1/2 life: 3 min
- slightly water soluble
- Indication: prevent angina due to CAD

21
Q

Example of Adhesive Dispersion

A

Rivastigmine (250 Da)
- sparingly water soluble
- very soluble in ethanol, acetonitrile, n-octanol, ethyl acetate
- LogP: 2.3 (in between)
- Indication: dementia associated with Alzheimer’s Disease/Parkinson’s
- 4.6mg/24h
- 9.5mg/24h
- 13.3/24h

22
Q

Example of Matrix Dispersion

A

Xulane
- 150 mcg/day norelgrstromin + 35 mcg/day EE
- Backing Layer: polymer layer for structure support
- Middle Layer: adhesive + matrix + drug
- Third Layer: release liner
- once a week for 3 weeks on upper arm, abdomen, butt, back

Warning
- smoking can cause CV risk
- risk of VTE
* risk is higher for patch than oral because Css is 65% higher

23
Q

Drug Diffusion in Skin

A
  1. across cellular-intercellular regions
  2. across lipid intercellular spaces
  3. across thin lipid layers sandwiched between flattened protein cells
24
Q

Factors Affecting Permeability

A

Hydration
- more hydrated, great drug permeability
- water with polar head groups of lipid bilayer loosens lipid packing

Solubility

Excipient
- solvent, surfactant

pH
- affects drug ionization status –> desire unionized drug

25
Q

Alternatives to Help With Permability

A

Iontophoresis
- uses low voltage electrical current to drive charged drugs through skin

Electroporation
- uses high voltage to create transient pores in skin

Ultrasound
- uses low frequency ultrasonic energy to disrupt stratum corneum

Prodrug
- makes lipophilic (hydrophobic)

Enhancers (most common): alcohol, DMSO, surfactant, acetone, ethyl acetate

26
Q

Ionic Surfactant

A

disorders lipid layer of stratum corneum to swell or leach out some structural components reducing resistance

27
Q

Ascorbate/Diothiothreitol

A

reducing agent that disrupts disulfide bonds of proteins in cells

28
Q

Azone

A

nonpolar, oil liquid that fluidizes intracellular lipid lamella of stratum corneum in the hydrophobic tails

29
Q

DMSO

A

dipolar solvent that enters the aqueous region of stratum corneum interacting with lipid polar heads to expand hydrophilic region between the heads

30
Q

Microneedles

A
  • make the holes mechanically

Type 1: pretreatment to increase permeability before patch is applied

Type 2: needles coated with drug and released while embedded into skin

31
Q

Common Errors

A

Preparation
- removal of patch from packaging
- removal of protective foil
- alternation of patch

Removal
Application
Monitoring heat
Storage

PHRM 829 Exam 3 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions