Drug Absorption Metabolism & Elimination Flashcards
(14 cards)
What is meant by absorption of drugs?
It is a process of the transport from site of administration to systemic circulation by crossing biological membrane
What are the factors that affect rate an extent of absorption of drug?
Environment where drug is absorbed,
chemical characteristics of drug,
route of administration (bioavailability)
What are the drugs that are transported by facilitated diffusion?
Corticosterone (organic cation transporter)
Ethacrynic acid (organic anion transporter)
Captopiril (dipeptide transporters including PEPT1)
PEPT1 is a dipeptide transporters that transports___
Captopiril
Anion transporters are for transporting ____
Ethacrynic acid through facilitated diffusion
Corticosterone is transported by facilitated diffusion by
Organic cation transporter (OCT)
OCT 2 — organic cation transporter is a transport protein found in ___
The kidney.
In the membrane of tubular epithelial cells in the PCT.
From where to where does OCT 2 transport cation drugs
From blood supplying the PCT to the inside of tubular epithelial cells
From where to where does “multi drug & toxin extrusion protein” (MATE) transport the cationic drug
From inside the cell into the tubular lumen for excretion in the urine.
What are the transport mechanisms of absorption of drugs from the GI tract
Passive diffusion
Carrier mediated transport
Endocytosis and exocytosis
Which vitamin is transported by endocytosis
Vitamin B12 across the gut wall
What are transported by exocytosis
Neurotransmitters— norepinephrine
Factors influencing absorption
•Ph (uncharged drug— high absorp)
•Blood flow (high aborp- intestine)
•Total surface area (microvilli)
•Contact time at abs. site (with food)
•Expression of p-glycoprotein (reduces drug absorption, pumps the drugs out of cells, in areas of high expression)
A drug will reach it steady state and how many half lives
4-5 half lives
