Pharmacology Flashcards
What type of process is conventional transdermal drug delivery and what is it driven by?
Passive process driven by diffusion
In topically applied drugs what is the rate of absorption described by?
Fick’s law
What can profoundly influence the rate and extent of absorption of a topically applied drug?
The vehicle
When drugs are applied topically what is the only factor providing the driving force for absorption?
The soluble fraction
The inclusion of what can enhance solubility and enhance absorption?
Excipients
Why are topically applied drugs generally poorly absorbed?
Because only a small fraction partitions into the stratum corneum
Give two factors which can improve partitioning?
Hydration of the skin by occlusion and inclusion of excipients
Give six factors which vary glucocorticosteroid penetration, potency and clinical effect?
- Body site
- State of the skin
- Occlusion
- Vehicle
- Concentration of drug
- Form of drug
What do glucocorticoids signal via?
Nuclear receptors (class 1), specifically GR a
How do glucocorticoids enter cells?
Lipophilic molecules - so by diffusion across the plasma membrane
Within the cytoplasm - what do glucocorticoids combine with to produce dissociation of inhibitory heat shock protiens?
GRa
Once glucocorticoids have combined with GRa in the cytoplasm to produce dissociation of inhibitory heat shock proteins - what occurs?
The activated receptor translocates to the nucleus aided by importins
In relation to the molecular mechanism of action of glucocorticoids - within the nucleus what do activated receptor monomers assemble into and bind to?
Homodimers and bind to glucocorticoid response elements GRE in the promotor region of specific genes
Where are drugs delivered by needles inserted into?
The fatty adipose tissue just beneath the surface of the skin
Why is absorption of subcutaneous delivered drugs slow?
Due to poor vascular supply
