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gastric juice
Orally administered drug must encounter the low pH in ________ and digestive enzymes.
bioavailability
the fraction of initial administered dose of the drug that reaches its intended site of action or the systemic circulation
drug absorption
transportation of the unmetabolised drug from the site of administration to the body circulatory system
drug elimination
irreversible removal of an administered drug from the body, or from the plasma/blood, via either
hydrophilic drugs
directly excreted by kidneys
hydrophobic drugs
metabolic biotransformation before excretion
route of administration rate of absorption drug distribution within the body rate of elimination
4 considerations of drug monitoring
intravenous
The most effective route of administering drugs is ______ because it is the most direct and bioavailability is at 100%
passive diffusion carrier-mediated membrane transport nonspecific drug transporters
3 mechanisms of drug absorption:
dissociation, solubility, diffusion
gastrointestinal drug absorption is dependent on:
_______ of the drug from its administered form
______ of the drug in gastrointestinal fluid
its ______ across the gastrointestinal membrane
changes in intestinal motility pH inflammation coadministration of certain foods or drugs age, pregnancy or other pathologic conditions
absorbance rate in small intestine can be altered by:
the stomach has thick mucous layer and short transit time thus limiting drug absorption Moreover, small intestine has the largest surface area for absorption and the membranes are more permeable
Rate of absorption is different in stomach compared to small intestine, why?
Drug distribution
transfer of the unmetabolised drug from one location in the body to another after absorption
protein concentration pH metabolic abnormalities presence of other chemicals
protein binding is influenced by:
blood perfusion blood & tissue binding proteins regional pH permeability of cell membranes body water composition fat composition diseases
drug distribution is impacted by:
Phase 1: introduction of functional group phase 2: conjugation of the drug molecule with another molecule
What are the two metabolic pathways of hepatic drug biotransformation?
cytochrome P450
What enzymes are involved in phase 1 of hepatic drug biotransformation?
The drug molecules become water soluble, allowing renal and biliary excretion
What happens after phase 2 of hepatic drug biotransformation occurs?
renal excretion
free fraction of the drugs or its metabolites is filtered in the kidneys, and excreted in the urine
feces, enterohepatic
biliary excretion is where the liver actively secretes ionised drugs into bile to be:
eliminated in ______; or
reabsorbed as part of the _______ cycle
Note 
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