1. ADME

Question 1

What is the blood brain barrier?

Answer 1

A layer of tightly joined epithelial cells which prevents drugs from entering the brain.
Lipid soluble drugs may enter by passive diffusion.
Water soluble drugs may enter by carrier mechanisms.
P-glycoprotein - active drug efflux pump.

Question 2

What 3 things can happen to drugs when being metabolised?

Answer 2

1. Converted to inactive metabolites.
2. converted to active metabolites.
3. Excreted unchanged.

Question 3

What happens in phase 1 drug metabolism?

Answer 3

The molecular structure of the drug is transformed, through oxidation, hydrolysis, reduction.
This adds polar groups or increases water solubility.
Can abolish activity of the drug.
Non/toxic metabolites produced.

Question 4

Enzyme involved in phase 1?

Answer 4

cytochrome p450 (CYP450)

Question 5

Phase 2 drug metabolism

Answer 5

Endogenous substance (e.g. sulphate) is attached to the parents drug of phase 1 metabolite.
This increases polarity/water solubility.

Question 6

Phase 2 enzymes are called…

Answer 6

…transferases

Question 7

alternative excretion routes to renal?

Answer 7

1. Biliary into intestine e.g. morphine
2. Sweat, saliva, expired air, tears.
3. Breast milk to baby - DANGEROUS.