Lec 2 Part 2 Way Of Passage Of Drug Through The Skin Flashcards
What are the ways of passage of drugs through the skin?
1_Transcellular
2_Intercellular
3_Transappendageal route
The transcellular route considered as a shorter path(T or F)
T
Give reason, transcellular diffusion involves higher resistance to the passage of substances.
Because they have to cross both lipophilic and hydrophilic structures.
Why there is a resistance in the transcellular route?
Because the drug must cross the lipophilic membrane of each cell, then the hydrophilic cellular contents containing keratin, and then the phospholipid bilayer of the cell one more time.
This series of steps repeated numerous times to traverse the full thickness of the stratum corneum.
The intercrllulare route greatly reduces the rate of drug penetration (T or F)
T
Skin appendages, namely hair shafts and sweet glands, form the only access to lipophilic drugs ( T or F)
F hydrophilic
The best route to the carticosteroids, elctrolytes, polar antibiotics is :
1_transcellular route
2_intercellular route
3_transappendageal route
(And give reason)
3_ transappengageal route is the best, because the skin appedages form the only access to hydrophilic drugs.
According to Fick’s Law, the diffusion is prportional to the concentration gradient (T or F)
T
According to Fick’s Law the J is the…….
The flux(the rate of transfer per unit area of surface )
dm/dt=
J
dm/dt is …..
The flux(the rate of transfer per unit area of surface)
Dx is the ….
Distance (thickness of the skin)
D is the….
Is the diffusion coefficient
C is the …
Is the concentration of diffusing substances
Why we said the pseudo-steady state is pseudo?
Because it does not start from the origin
