ADME Flashcards
F = AUC(non-IV) / AUC(IV) x 100%
Bioavailability fraction
determinants of Drug Absorption
solubility concentration local blood flow Surface Area ability to permeate cell membrane
in order to be absorbed, drug must be
process called?
dissolved into aqueous phase (of extracellular fluid)
dissolution
rate absorption rates of different drug vehicles
Aq soln. > Aq suspension > oily vehicle > pellet/solids
for drugs that easily permeate cell membranes, _________ can be the RLS for absorption
local blood flow
5 processes of membrane permeation
PASSIVE DIFFUSION facilitated diffusion filtration active transport pinocytosis/phagocytosis
net rate of diffusion determined by
drug size (hydrated radius/MW) lipid (water partition coefficient) net charge
______ forms (COOH, NH2) of drugs permeate membranes easily
neutral
When Lidocaine is injected into inflamed tissue it becomes a _____ which _____ its onset of action
cation
delays
passage through small intercellular gaps between endothelial cells
filtration
VRG v. VPG
vessel rich group
v.
vessel poor group
in the initial phase of distribution the drug moves to _____ then in the Redistribution phase moves to
VRG (brain)
VPG (adipose)
decreases apparent volume of distribution and intensity of clinical effects. But increases half-life and incidence of drug interactions
Plasma protein binding
elimination is typically more efficient for
hydrophilic drugs
primary organ responsible for biotransformation of most drugs
liver
Total Body Clearance
theoretical measure of the plasma volume cleared of a drug in a given amt of time.
Vd x Ke
(sum of individual organ rates for first order elimination)
Renal clearance involves these 3 processes
clearance =
glomerular filtration
tubular secretion
tubular reabsorpton
(GF + TS - TR)
tubular _______ is active
tubular ______ is passive
secretion
reabsorption
First Pass Effect
extent to which an orally administered drug is metabolized during its first pass through portal circulation (ranges from 0-100%!)
The liver will usually
render drugs more polar, increase their solubility in plasma
2 Categories of biotransformation by liver?
Phase 1 Rxns - (cytochrome P enzymes)
Phase 2 Rxns - (coupling with endogenous substance)
Drugs that are metabolized by the same family of hepatic CYP isozymes can?
compete as substrates with one another
drugs that act as ______ of CYP isozymes, will reduce/prevent the metabolism of other drugs by that family
inhibitors
drugs that act as ____ of CYP isozymes, cause an elevated rate of drug metabolism by those isozymes
inducers
metabolism Does/Does not? always lead to drug inactivation?
does not
use clearance rate of _______ to adjust dose of animal with renal disease
creatine
