4bby1040 Flashcards
affinity high vs low
potent?
the higher affinity a drug has to a specific receptors, the more likely the bind and stay bounds to it - higher potent
the lower affinity a drug has to a specific receptors, the less likely the drug will bind and stay bounds to it - low potent
Potency
the drug concentration required to produce a given level of biological response
Comparing EC50 values for two drugs with the same action allows us to calculate their relative potencies AKA potency ratio
In virtue
definiton
response
drug effect on a tissues or cells kept alive outside the body
Measure the change in the (tension of muscle or activity of enzyme)
In Vivo
drug effects are studied in the living animal/human
Ex Vivo
tissues or organ is removed from an animal that has been treated with a drug and testing for the long-term effect the drug has on the organ function
the max effect (EMAX)
indicates the max responses the drug can produces (concentration-response graph)
EC50
The molar concentration of a drug that produce 50% of the maximum response for the drugs
M potency ratio
M= EC50(test)/EC50(standard)
Or
Log M = Log EC50(test) – Log EC50 (standard)
A potency ratio (M) less than 1 , this means the test drug is more potent than the standard drug
M is greater than 1 than the standard drug is more potent than the test drug
Bioassay:
It’s a technique where the potency of a drug is determined by measuring the biological response it produces
Comparing the low and high concentration of one drug to the low and high concentrations of another drug
Therapeutic index:
Is the ratio between the toxic doses and the dose producing the desired therapeutic effect
Higher Therapeutic index is, the less chance of the drug producing toxic side effects
Therapeutic Index = LD 50 / ED 50
LD 50 = lethal does in 50 % of population
ED 50 = Effective does in 50% of population
Receptor
a protein - random collisions between the drug molecules and receptor
Affinity:
The molar concentration of drug required to occupy 50% of the receptors at equilibrium
( binds to the receptor)
Kd
a measure of the affinity of a drug for a receptor
a drug with high affinity will have a low Kd
Efficacy
The ability of a drug to activate a receptor
Response
Agonists
bind and activate the receptor contain efficacy
a conformational change
lead response to the tissues/ cells
Agonists full/ partial - affinity/ efficacy
Full: Has affinity and high efficacy – maximal response every time
Partial: has affinity but low efficacy – low effective – fail to produce max response
Antagonist
Acts as inhibits
Inhibits the effects of neurotransmitter or hormones
acts on the receptor
antagonists forms
chemical
pharmacokinetic
physiological
1) Chemical: use one drug to chemically inactivate another – receptors are not involved
2) Pharmacokinetic: one drug alters the way the body deals with another – receptors are not involved
3) Physiological: Two drugs act to produce opposing effects- cancelling each other out
Competitive antagonists
Complete with the agonist for the same site on the receptor molecule – don’t activate it –has affinity but zero efficacy – can be reversible or irreversible (covalent bond)
Non-competitive antagonists:
Act at a different site on the receptor or another molecule - can be reversible or irreversible (covalent bond)
Reversible competitive antagonists
overcome?
shift?
- Can be overcome by increasing the concentration of the agonist – its surmountable
- Parallel shift to the right
Irreversible competitive antagonist
overcome?
- the inhibition they produce is not overcome by increasing the agonist concentration- it’s not surmountable
with efficacy / no efficacy - response
with - forms is a response
without -does not form a response
