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Flashcards in Topicals Deck (39):
1

What is in Osurnia?

1% florfenicol 1% terbinafine 0.1% betamethasone

2

What are some factors that affect penetration of topical therapies?

  • Concentration
  • Thickness and integrity of the SC
  • Frequency of application
  • Occlusion of vehicle
  • Compliance 

3

TRUE or FALSE

Only the vehicle can cause local toxicity for topical products. 

FALSE

Either the vehicle or active ingredient can cause local toxicity for topical products. 

4

TRUE/FALSE

Topical medications cannot induce systemic toxicity. 

FALSE

Topical medications can induce systemic toxicity. 

5

What is the three phase model of drug action?

  1. Pharmaceutical phase
    1. Application of drug-vehicle combination
  2. Pharmacokinetic phase
    1. Penetration/permeation
  3. Pharmacodynamic phase
    1. Interaction with receptors on normal or diseased skin 

6

TRUE/FALSE

For all topical products, diffusion is determined by the stratum corneum. 

TRUE

For all topical products, diffusion is determined by the stratum corneum. 

7

TRUE/FALSE

Diffusion across intercellular lipids is 10-fold less than the lipids in cellular membranes. 

FALSE

Diffusion across intercellular lipids is 1000-fold less than the lipids in cellular membranes. 

8

Does dilution of topical products occur when compounds pass from the SC into the viable epidermis? 

Yes. This is due to increased tissue volume and lower resistance. 

9

When it comes to topical products - what does "resorption" refer to?

Uptake of compounds by the cutaneous microvasculature 

10

TRUE/FALSE

Resorption of topical products is directly proportional to capullary surface area. 

TRUE

Resorption of topical products is directly proportional to capullary surface area. 

11

TRUE/FALSE

The ionized fraction of a topical product is what diffuses across the SC. 

FALSE

The unionized fraction of a topical product is what diffuses across the SC. 

12

What are some idea qualities for a topical vehicle?

  • Chemically stable
  • Physically stable 
  • Does not inactivate the drug 
  • Non-irritating 
  • Non-allergenic 
  • Cosmetically acceptable 

13

What are the main indications for using a powder? 

Drying

Lubrication of an intertriginous area

[absorb moisture, decrease friction]

14

If you add a powder to: 

water you make a ___________

liquid you make a ___________

ointment you make a _________

If you add a powder to: 

water you make a rinse

liquid you make a shake lotion

ointment you make a paste

15

What is talc?

Magnesium silicate 

16

What is a poultice?

A soft, moist mass of material, typically of plant material or flour, applied to the body to relieve soreness and inflammation and kept in place with a cloth.

A image thumb
17

TRUE/FALSE

Ointments are more lubricating than creams

TRUE

Ointments are more lubricating than creams

18

The amount of substance crossing the skin per unit area per unit time defines which of the following terms?

A. Accumulation.
B. Penetration.
C. Absorption.
D. Supersaturation.

The amount of substance crossing the skin per unit area per unit time defines which of the following terms?

A. Accumulation.
​B. Penetration.
C. Absorption.
D. Supersaturation.

19

Which of the following effects is seen with increased pH?

A - Increased desquamation.

B - Decreased desquamation.

C - Facilitation of sphingomyelinase.

D - Increased barrier function.

Which of the following effects is seen with increased pH?

A - Increased desquamation.

B - Decreased desquamation.

C - Facilitation of sphingomyelinase.

D - Increased barrier function.

20

According to Fick’s equation, which of the following will increase flux across the epidermis?

A: High concentration of the substance in the skin before application.

B: High partition coefficient.

C: High skin thickness.

D: Low diffusivity.

According to Fick’s equation, which of the following will increase flux across the epidermis?

A: High concentration of the substance in the skin before application.

B: High partition coefficient.

C: High skin thickness.

D: Low diffusivity

21

The extracellular space of the stratum corneum is described as which of the following?

A. Hydrophobic.
B. Hydrophilic.
C. Neutral in polarity.
D. Both hydrophobic and hydrophilic.

The extracellular space of the stratum corneum is described as which of the following?

A. Hydrophobic.
B. Hydrophilic.
C. Neutral in polarity.
D. Both hydrophobic and hydrophilic.

22

Describe the function of antiseborrheic products & define keratoplastic and keratolytic.  

Antiseborrheic products function by normalizing keratinocyte turnover rates.  Most antiseborrheic agents function by reducing epidermal division (keratoplastic) and by normalizing keratinization and by increasing desquamation (keratolytic).

23

Describe the potency of topical glucocorticoids - ie what is the most potent vehicle if the steroid type and concentration is the same. 

The anti‑inflammatory potency of topical glucocorticoids is highly variable depending on the type of glucocorticoid and the vehicle. This tends to be more important in products that are left on the skin surface such as sprays, lotions, creams and ointments, then shampoos, which   are rinsed off the skin and hair coat. The vehicle is important in determining efficacy as well as    systemic toxicity.  The more occlusive the vehicle the more potent the product.  Ointments are more potent followed by creams, lotions and gels - assuming the glucocorticoid and concentration is comparable. 

24

What are the common adverse reactions to topical corticosteroid use?

Atrophy, scaling, comedones, alopecia, pyoderma, milia, calcinosis cutis; axillae, groin, flanks; pinnal curl 

25

Please describe the three-phase model of drug action as it is applied to topical therapy.  

1.    The initial pharmaceutical phase is represented by application of a drug-vehicle combination to the skin. Studies on the importance of the vehicle deal with this phase

2.    The pharmacokinetic phase covers the penetration and permeation of the drug into the skin. After permeation of the skin, no further therapeutic effect in the skin is expected. Systemic effects follow.

3.    The pharmacodynamic phase refers to the interaction of the drug with receptors in the normal or diseased skin.

26

In order to undergo percutaneous absorption, a compound must:

  • Be released from its formulation
  • Encounter the skin surface
  • Penetrate the stratum corneum
  • Diffuse through the viable epidermis into the dermis
  • Gain access to the systemic compartment through the vascular system
  • Diffuse through the dermal and hypodermal layers to reach an underlying target tissue

27

The primary compartment that limits the percutaneous absorption of compounds is the _______ ________. 

The primary compartment that limits the percutaneous absorption of compounds is the stratum corneum.

28

What three factors determine the feasibility of transdermal delivery for any particular compound?

                  Hydrophobicity, molecular weight, and ionic charge

29

What is the mechanism of action for Selenium Sulfide?

Alters the epidermal turnover rate and interferes with the hydrogen bond formation in keratin. It is keratolytic, keratoplastic and very degreasing. It is reported to have some residual adherence to the skin. Has sporocidal activity.

30

Can you discuss the barrier properties of the skin? 

A major component of this barrier is extracellular lipids– extruded into the extracellular space as cells transition from the granular layer to the stratum corneum; brick and mortar model; predominated by ceramides, cholesterol and free fatty acids; it is formed by the conversion of lipids extruded from lamellar bodies in the stratum granulosum (glucosylceramides, sphingomyelin, cholesterol, phospholipids); enzymes convert these precursor lipids to final product (b-glucocerebrosidase, acid sphingomyelinase, secretory phospholipase A2 and proteases). 

Acidification of the extracellular space of the stratum granulosum and stratum corneum is also very important; the “acid mantle” is created primarily via two mechanisms – 1) non-energy dependent sodium-proton exchanger on the surface of upper epidermal keratinocytes which pumps protons extracellularly; 2) conversion of phospholipids into free fatty acids via phospholipase A2 which provides an acid environment since they have acidic moieties; acidic environment is necessary for optimal activity of (b-glucocerebrosidase and acid sphingomyelinase which convert sphingolipids into ceramides; the acidic environment also limits degradation of corneodesmosomes (Dsg1) by proteases – limiting desquamation; 
decrease pH, decrease desquamation 

31

What is Fick's law? 

J = KD/h (c0-c1)

J = flux/unit area, K = partition coefficient (hydrophilicity), D = diffusibility; h = skin thickness c0= concentration of substance applied; c1= often set to zero since it is how much substance is already in the skin 

A passive diffusion model! 

32

You are reaching for a topical steroid for a patient. What are the mechanisms of action that you have in mind? List 3. 

  • Non-specific anti-inflammatory agent
  • Induce annexin (phospholipase-A2-alpha inhibitory protein) in cells to block release of arachidonic acid and its conversion to eicosanoids
  • Inhibit cytokine synthesis (IL-1, TNFa) via inhibition of NF-kb
  • Reduce DNA synthesis via antimitotic effect on epidermal cells
  • Inhibit migration of leukocytes and macrophages to the area where applied – inhibiting erythema, pruritus, edema, etc. 
     

33

What is the purpose of using phytosphingosine salicyloyl (Douxo calm)? 

This is a modified pro-ceramide with salicylic acid which serves as a key molecule in the natural defense mechanism of the skin; ceramides comprise 40-50% of the main lipids responsible for maintaining the cohesion of the stratum corneum, the skin lipid barrier controlling local flora (antibacterial/antifungal) and maintaining moisture balance; anti-inflammatory with anti-IL-1 activity, impairs production of prostaglandin E2 and inhibits protein kinase C 
 

34

What is the mechanism of action of chlorhexidine gluconate?

Phenol-related bisanguinide; acts by damaging bacterial cytoplasmic membranes; antifungal activity is obtained when the concentration is greater than 2% 

35

What is the mechanism of action of ethyl lactate?

Very lipid soluble compound that rapidly penetrates hair follicles and sebaceous glands; hydrolyzed by bacterial lipases into lactic acid and ethanol; the free lactic acid lowers the skin pH (antibacterial); ethanol will solubilize fat and lower sebaceous secretions

36

What is the mechanism of action of hypochlorous acid?

Broad-spectrum antimicrobial with rapid activity against gram +/- infections, yeast/fungus, virus; strong oxidant; main route of attack is via disruption of the cellular membrane; increases blood flow to area 

37

What are the mechanisms of action for sulfur?

Lower concentrations – keratoplastic– assisting conversion of cysteine to cystine (an important factor in corneocyte maturation); Higher concentrations – keratolytic– via interactions with cysteine to form hydrogen sulfide (H2S); antibacterial, antifungal, antiparasitic– secondary to sulfur conversion to H2S and pentathionic acid by bacteria and keratinocytes; used for scabies and acne treatment in humans (6%) 

38

What are the mechanisms of action for salicylic acid?

Mildly antipruritic, antibacterial (bacteriostatic), keratoplastic [low; 0.1-2%] and keratolytic [high; 3-6%]; lowers skin pH, increases corneocyte hydration, dissolves intercellular binder between corneocytes 

39

What product is sulfur synergistic with?

Salicylic acid