316 Biopharmaceutics

ndifranco94's version from 2015-10-13 20:13


Question Answer
ADMEAbsorption, Distribution, Metabolism, Excretion
Disposition categoriesDistribution, Elimination
Elimination categoriesMetabolism, Excretion
Absorptionmechanisms of drug input into the body and into a tissue or an organ within the body
Dispositiondistribution and elimination of a drug after it enters the systemic circulation
Distributionreversible transfer of a drug b/n one compartment to other in the body. Measured by conc of drug in blood, organs, tissues
Eliminationchem. transformation and/or physical removal of a drug from the body
Metabolismchem. transformation of a drug in the body
Excretionprocess by which a drug or metabolite is removed from the body w/out further chemical modification
First pass organsintestine, liver, lungs
Enterohepatic recirculation organsintestine, liver, gallbladder
Stomachmajor site of chemical and enzymatic degradation; low absorption
Most absorption occurs inthe intestine
Transit time in the small intestine2-4 hours
What controls blood drug concentration-time profileGastric empty rate
Complete emptying of the stomcahup to 5 hours
Duodenum and proximal jejunumhave highest surface area, major sites of drug absorption
Colon570 times less absorptive surface area than the small intestine, BUT transit time 12-72 hours so it is a good site for prolonged drug release and absorption
High absorption rate effect on drug blood concincreases drug blood conc
High elimination rate effect on drug blood concdecreases drug blood conc
Factors affecting bioavailabilityfirst-pass metabolism, water solubility/absorption of dosage forms, residence time in the GI tract, physical condition of patients, reaction of drugs in GI tract
Enterohepatic circulationunmetabolized drug is pass from liver back to the GI tract
Major organ for metabolismliver
Which drugs are more likely to be excreted in bilepolar and lipophilic groups
Drug w/ high renal excretion haslow biliary excretion
Major organ for excretionkidneys
What kind of drug can the kidney remove?unbound drugs
Glomerulus size cutoffless than 8nm
How are solutes removed from kidneysactive transport
Drug filteringfiltered by glomerulus and reabsorbed into bloodstream by distal tubule
Negatively charged moleculesretained b/c of repulsion w/ Bowman's capsule
Long linear moleculesmore easily eliminated b/c they snake through glomerulus
Overton rulethe more soluble in lipids a drug is, the greater its permeability through a cell membrane
FAcilitative transporttransport facilitated by transmembrane proteins/transporters W/OUT NRG
Primary active transportNRG + transporters needed to drive drug across membrane
Secondary active transportSymport and Antiport
Symporttwo molecules move into cell at once
Antiportone molecule in, one out
Efflux transporterspump substrates out
Influex transporterstransfer substrates in
BBBP-gp efflux pumps + tight juxns that prevent paracellular transport
How to deliver to braininhibit P-gp efflux pumps, or tumor