Drug Absorption Flashcards
Four basic factors that determine drug pharmakinetics
Absorption
Distribution
Metabolism
Elimination
Define absorption
The process of movement of uncharged drug from site of administration to the systemic circulation
How quickly the drug will get into the system at a sufficient amount
Tmax
Maximum concentration achieved (peak concentration)
Cmax
All the amount of drug that has gone into systemic circulation
Area Under Curve (AUC)
A drug given IV has _____ Bio-availability
100%
The amount of drug in circulation
Bioavailability
Factors that effect bioavailability
Formulation
Ability of drug to pass physiological barriers
Gastrointestinal effects
First pass metabolism
First Pass Metabolism
Drugs that are absorbed via the GIT are circulated to the liver first via the hepatic portal vein
The liver acts as a filter and only part of the drug is circulated systemically
A physiological barrier
Transport membranes
Actions across transport membranes
Passive diffusion Filtration Bulk flow Active transport Facilitated diffusion Ion-pair transport Endocytosis
Most drugs completely ionise in water (True or False)
False
Only non-ionised (non-polar) drugs diffuse across the membrane (True or False)
True
Most drugs are not weak acids or bases (True/False)
False
Does the degree of ionisation depend on the PH of the environment as well as the drug
Yes