ADME Excretion Flashcards
What is Excretion?
Removal of the drug (and metabolites) from the body
Where does Excretion primarily occur?
The kidneys.
altho a small amount of excretion can occur from the lungs, sweat, saliva etc.
What is Tonal Renal Excretion of a drug?
the glomerular filtration, active tubular secretion and tubular re-absorption
what does Glomerular filtration depend on?
depends on systemic BP and renal blood flow
Glomerular filtration is a ____ process?
Passive
What factors sifnificantly affect a drugs likely hood of being filtered?
Molecular size, charge, and protein binding.
Drugs that are very small < 7,000 Da will be?
freely filtered weather charged or uncharged
Drugs that are larger (7,000-70,000Da) will be?
filtered according to their mass. Drugs larger than 70,000 are less likely to be filtered through the normal glomerulus esp if they carry charge (repelled by neg charge basal cell membrane proteins)
Where does active tubular secretion occur?
Proximal Convoluted tubules
In active tubular Secretion…
drugs are moved against a concentration gradient using energy dependent. allows a higher concentration to be achieved in the filtrate.
Active tubular secretion allows…
ionized drugs and protein-bound drugs to more
Active tubular secretion is subject to?
saturation and inhibition
Organic Cation transporters OCT’s move…
organic bases
Organic Anion transporters OAT move…
Organic acids
Where does tubular rebsorption take place?
passive diffusion occurs in the proximal and distal convoluted tubules. Lipid soluable / nonionized drugs have the greatest chance of moving back into circulation
