distribution and elimination Flashcards
distribution factors
diffusibility and solubility
membrane and drug
drug concentration body’s site of action
duration and elimination
membrane diffusibility
membranes need to maintain a certain electrical potential in order to survive
have to keep balance of ions on either side
permeability
capillaries
vascular system composed of tightly packed cells that allow for minimal transmission across membranes
affect molecule movement
active diffusion
often used to get rid of chemicals
ion pumps
uses energy
passive diffusion
transport proteins
molecule: lipid-soluble, simple chain, uncharged
relies on shape of molecule to pass
blood brain barrier diffusiblity
no diffusibility
capillaries form tight junctions, don’t allow for passage
placental “barrier”
semi permeable membrane- not a barrier
maternal blood vessel and blood controls for rate of exchange
can slow down
elimination
depends on intake method, liver (enzymes and metabolism) and toxicity of metabolites
what organ is always involved in elimination
kidney
livers role in elimination
proliferates enzymes and bile to deactivate drug
first pass metabolism - what happens once drug reaches SOA
toxicity of metabolites role in elimination
HIGH toxicity –> zero order ran (linear)
LOW toxicity–> first order reaction (parabola)
what type of reaction is an overdose
zero order
what does urinalysis test
the metabolites- drug has already been broken down and used
what does a blood sample test
the drug
problems - detection time < elimination time
more likely to detect metabolites
individual differences play a factor
negative results might not confirm non use
what are some other methods of drug analysis
hair analysis - longer detection period and less likely to tamper
oral fluid- robust to tampering, but relies on intake method (around 3 days)
