Basic Pharmacology and Pharmacokinetics

Question 1

What is the difference between ‘empirical’ and ‘rational’ drug discovery?

Answer 1

Empirical - drug discovered after functional useful effect

Rational - drug designed for a certain function

Question 2

What does Km indicate in enzyme rate of reaction?

Answer 2

Affinity for a paritcular substance

Km is [substrate] at 1/2 V max

Question 3

What does Kcat measure?

Answer 3

turnover number of an enzyme ie. how fast a specific enzyme can catalyse a certain reaction

measured per second

Question 4

What are the ‘real-world’ limitations of Michaelis-Menten kinetics?

Answer 4

1) Substrate aren’t freely moving (cytoplasm is more like gel)

2) Heterogenous enzyme reaction - bound to membrane

3) Homogenous enzyme reaction - E or S mobility restricted

Question 5

How does is polymorphism affect drug action?

Answer 5

Genetic variation may result in variation in protein (enzyme) formed, this variation in enzymes may cause a variation in drug action eg. different ezyme structure may have lower affinity for drug (higher Km)

Question 6

What is a drugs journey throught the body?

Answer 6

• Absorption
• Distribution
• Metabolism
• Excretion

ADME

Question 7

What is a drugs half-life and is it constant?

Answer 7

The time taken for the drug plasma concentration to half
In theory half-life is constant, however due to the variability of the body functions, it is not in reality

Question 8

What is Cmax and Tmax?

Answer 8

Cmax - highest concentration

Tmax - time at Cmax

Question 9

What are physioichemical properties that must be considered during pre-formulation?

Answer 9

• logP affects permeability
• Molecular weight affects ability to absorb
• pKa affects ionisation state at specific pH which affects absorption
• ## Water solubility