Pharmacokinetics Flashcards
what is pharmacokinetics?
the study of absorption
distribution
biotransformation
excretion of drug is called —
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11-2-2025
10.41PM
what is Absorption ?
it is the process by which drug enters into the circulation (systemic/portal) from its site of administration across the biological membrane
why not IV + Intra-arterial ?
in this case drugs needs to be absorbed
rather they enter into the circulation directly
types of drug absorption ?
simple/passive
specialized
simple absorption process >
simple/lipid diffusion
filtration / aqueous diffusion
specialized transport process ?
active
facilitated
phagocytosis
pinocytosis
endocytosis
exocytosis
simple D VS Active D ?
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Simple D all content ?
towards the electric gradient
no - energy + membrane + carrier protein
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Active transport contents ?
against the conc/electrical gradient
energy + membrane + CP
facilitated diffusion example ?
Vitamin B12 absorption
tetracycline
glucose
pyrimidine
fat soluble vitamins
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facilitated d definition?
diffusion of drug through a biological membrane
along the conc / electro-chemical gradient
with the help of a carrier protein
Simple D vs Faciliated D ?
80
route of administration for drug absorption?
IM>SC>O
lipid solubility and A ?
inc Lipid solubility = inc absorption
degree of ionization and absorption >
more I = more water soluble = less lipid soluble = less absorption
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high dose & A ?
high dose = inc conc of drug
dosage formulation ?
suspension > capsule > tablet
why suspension more absorption <
direct
why tablet less absorption >
tablet —— disintegration —- dissolution —— absorption
pk of drug & Absorption ?
less pKa
more ionization
drugs molecules draw water molecules from the solution duw=e to electrostatic charge
form hydrostatic shell which has larger size than the actual drug size
less penetration
more water soluble
less lipid soluble
bioavailability def ?
90
it is defined as the fraction of unchanged drug
reching the systemic circulation
sites of pre-systemic clerance ?
liver
lung
stomach
intestinal wall
first pass metabolism ?
the elimination/metabolism of drug
that occurs after administration
but
before its enter into the systemic circulation
drug distribution ?
it is the process by which drug reversibly leaves the blood stream and enters into the intestitium / cells of the tissues
free drug vs PPB drug ?
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significance of PPB ?
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Volume distribution of PPB ?
less
as high PPB restricts a drug into the vascular compartments
duration of action of PPB ?
long acting
as unavailable for metabolism / excretion
volume of distribution defination ?
it is defined as the virtual volume pf plasma that
would contain the total body content of the drug
at a conc equal to the plasma
Vd = ?
total amount of drug / plasma conc of drug
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11.46PM
