F8. Quantifying drug action

Question 1

What is a bioassay?

Answer 1

used to quantify drug action as a functional response. a method for measuring the effect of a substance on a living system to determine its potency or concentration ONE NOTE

Question 2

What are the types of bioassay?

Answer 2

cellular, tissue, organ, organ system (vary from simple to complex). Different types of bioassay can assess drug function at different levels of complexity. ONE NOTE- example

Question 3

Describe simple, (cellular) type of bioassay

Answer 3

-Well defined receptor types (e.g. recombinant), signalling pathways
-cell lines may not behave as the cells in actual organ,
response measured can be distant from actual function

Question 4

Describe complex, (organ and organ system) system type of bioassay

Answer 4

-Increasingly close to “real” physiology
-Many different receptor types
-Response is a composite of many effects on different cells / tissues

Question 5

unit conversions with moles

Answer 5

ONE NOTE
pM, nM, uM, mM, M

Question 6

Describe linear scale

Answer 6

Next point on the linear scale after x is x + constant ONE NOTE

Question 7

Describe log scale

Answer 7

Next point on the log10 scale after x is 10x (10 fold increase) ONE NOTE

Question 8

Why do we use logs in a concentration response curve?

Answer 8

With a linear concentration
scale, poor representation of
most points - cannot be
distinguished from 0, ONE NOTE

Question 9

What is the Rmax?

Answer 9

The maximal response to the agonist drug

Question 10

what is EC50?

Answer 10

Effective agonist Concentration to generate 50 % of that
agonist’s maximal response. A measure of agonist potency ONE NOTE

Question 11

what kind of curve is the CRC relationship described as?

Answer 11

sigmoid curve

Question 12

R equation?

Answer 12

R= Rmax. [D] / [D] + EC50 (ONE NOTE)
-When [D] = EC50 concentration
-Response (R) = 0.5 x Rmax

Question 13

How to compare agonists?

Answer 13

ONE NOTE

Question 14

what is potency and efficiency?

Answer 14

Potency is an expression of the activity of a drug in terms of the concentration or amount of the drug required to produce a defined effect, whereas clinical efficacy judges the therapeutic effectiveness of the drug in humans

Question 15

potency is determined by?

Answer 15

EC50 value

Question 16

efficacy is determined by?

Answer 16

Rmax

Question 17

what is a partial agonist?

Answer 17

drugs that bind to a receptor but produce a less than maximal effect. They have a lower intrinsic activity than full agonists, meaning they produce less than the full agonist effects. e.g salbutamol