Pharmacokinetics of drugs. Routes of drug administration

seminar 3

what is pharmcokinetics

what the body does to a drug

what is ADME

Absorption, distribution , metabolism , excertion

what four ways can drugs be absorped

\-passive diffusion

\-facilitated diffusion

\-active transport

\-endocytosis

what is passive diffusion

drugs move from high conc to low conc

how do water soluble drugs move through in passive diffusion

channel or pore

how do lipid soluble drugs pass through the membrane

without anything

what factor effect lipid solubilty

\-ionisation of weak acids and bases

\-lipid solubility

what is facilitated diffusion

high to low conc with help from carrier protein in the membrane

what is does active transport use

atp

where does active transport get the energy to move from low conc to high conc

when atp goes to Adp it releases energy

what is endocytosis

engulfment by cell membrane

what is transporter for glucose

SLC2A1

What does SLC5A1 and slc5a2 transport?

glucose and sodium

what is bioavailability ?

the fraction absorbed into the systemic circulation is the drugs bioavalibilty

what is the equation for bioavalibity ?

=AUC oral drug/ AUC iv drug x 100

what factors distribution ?

\-lipophilty

\-blood flow(brain recieves blood faster so if drug passes bbb it accumulates there)

\-capillary permeability

\-biding to plasma & tissue binding

\-volume of distubtion

what do drugs bind to in the plasma which slows down drug distrubtion ?

\

albumin

how do you work out volume of distrubtion

amount of drug in the body/concentration of drug in blood plasma

what does the volume of distrbution acutally mean ?

to calculate if blood will accumulate more in the blood or tissues

what drug is eliminated by zero order kinetics

asprin

what does the liver turn lipohilic drugs into that help the kidneys

water soluble molecules

what is phase 1 in the liver

making drugs more hydrophillic (water soluble )

what processes happen in phase 1 to turn them lipohillic

oxdiation reduction and hydrolisis

what is the main enzyme in phase 1

cytochrome p450

what is phase 2

if the drug is still to lipohilic to convert it more to hydrophillic

what happens in phase 2

gluathione coagulation , acetylation , sulfation and Glucuronidation

what are the steps in renal excertion

glomerular filtration , tubular secretion , tubular reabsorption passive

what other routes can drugs be exreted

\-bile

\-feces

\-lungs

\-breast milk

\-sweat glands