DD- Topical Therapeutics in Dermatology Flashcards
(37 cards)
To be effective, topical medications need to gain entry into the skin through the _______ and reach the site of action in desired concentrations
stratum corneum
1- Meds move across the stratum corneum by passive diffusion.
2- the agents can be transported through channels or pores within a lacunar system in the stratum corneum.
3- Meds may be transported via _________ such as sweat glands or hair follicles.
appendageal structures
Factors Influencing Absorption of Topical Medications
(a) drug factors and (b) patient factors.
Drug factors affecting percutaneous absorption include
- Active drug concentration
- Composition of the vehicle
- Molecular size of the drug or prodrug
- Lipophilicity of the drug
Molecular size of the drug affects its absorption at the site______
of action.
1- Meds move across the stratum corneum by passive diffusion.
2- the agents can be transported through channels or pores within ______ system in the stratum corneum.
3- Meds may be transported via appendageal structures, such as sweat glands or hair follicles.
a lacunar
Patient factors affecting percutaneous absorption of topical medications include:
- Presence of barrier disruption
- Anatomic location (including thickness of the stratum corneum)
- Skin hydration
- Occlusion
________of the skin often leads to markedly increased skin hydration.
Why does this matter?
Occlusion
active ingredients delivered in the form of an ointment, tape, or to the skin folds, reach much higher [ ] because occlusion prevents loss of medication by evaporation, friction, or exfoliation.
In general absorption is lower in anatomic regions where the_______ is thicker,
stratum corneum
1- Meds move across the stratum corneum by ________
2- the agents can be transported through channels or pores within a lacunar system in the stratum corneum.
3- Meds may be transported via appendageal structures, such as sweat glands or hair follicles.
passive diffusion.
Typically, the diffusion of a compound is
inversely proportional to the?
molecular size of the drug.
- Ointments: Water in oil emulsion
- Creams: Oil in water emulsion
- Gels: Semisolid emulsion in alcohol base
- Lotions/Solutions: Powder in water (some oil in water)
- Foams: pressurized collections of gaseous bubbles in a matrix of liquid film
These are examples of?
Classification of Vehicles
strong potency
hydrating, with very low sensitization risk or irritation risk
use are non-intertreginous sites
Ointments Vehicles
moderate potency
some hydration
significant sensitization risk and a low irritation risk.
Creams Vehicles
strong potency
drying
significant sensitization risk and a relatively high irritation risk
oral mucosal surfaces and the scalp
Gels Vehicles
matrix is stable at room temperature but
readily melts at body temperature.
supersaturated active ingredients to interact with lipids of the stratum corneum.
Foams Vehicles
When selecting an appropriate vehicle, three factors are of particular importance?
anatomic location, contact allergy/sensitization, and irritancy
What is an FTU?
FTU=Fingertip Unit
• 1 gram of cream covers approximately ______ area of skin
10 cm x 10cm
• 1 gram of ointment spreads ____ further than the same amount of cream.
10%
• Approximately _____ are necessary to treat the entire body of an adult man
20 g
binding of glucocorticosteroids is associated with the following downstream molecular events:
Alteration of transcription rate–> inflammatory proteins
Inhibition of nuclear factor-κB pathway
interacts with other tx factors that play a role in the inflammatory response.
Easy to apply/remove, non-toxic, non-irritating, stable, cosmetically acceptable, good at
delivering the drug, and inert
The ideal vehicle
Water-based vehicles (__________) contain preservatives that may increase the risk of contact allergy and sensitization.
such as creams, lotions, and solutions
