Optimising leads

Question 1

Adding alkyl groups to a molecule will make it more hydrophobic. True or false?

Answer 1

True

Question 2

What is steric shielding used for?

Answer 2

To alter chemical and metabolic stability

Question 3

Steric shielding hinders attacks by nucleophiles or enzymes. True or false?

Answer 3

True

Question 4

Changing an ester to an amide decreases stability. True or false?

Answer 4

False - increases

Question 5

What is the purpose of introducing medically susceptible groups to a molecule?

Answer 5

To decrease drug’s lifetime

Question 6

Esters are used to mask polar and ionisable COOH. True or false?

Answer 6

True

Question 7

Levodopa is decarboxylated in the cell to dopamine. True or false?

Answer 7

True

Question 8

Why can’t dopamine cross the BBB?

Answer 8

Because it is too polar

Question 9

Levodopa is a prodrug for dopamine. True or false?

Answer 9

True

Question 10

Enalapril is a prodrug for enalaprilit. True or false?

Answer 10

True

Question 11

What effect does masking polar groups have?

Answer 11

Reduced rate of excretion

Question 12

Azathioprine is a prodrug for 6-mercaptopurine. True or false?

Answer 12

True - polar group on azathioprine is masked to increase lifetime of drug and prevent it from being excreted as quickly

Question 13

Valium (diazepam) is a prodrug for nordiazepam. True or false?

Answer 13

True

Question 14

What are prodrugs used for?

Answer 14

For membrane permeability or to prolong activity of drug, mask toxicity and side effects, mask taste

Question 15

Aspirin is used as a prodrug for salicylic acid. Why?

Answer 15

Because the phenol on salicylic acid causes stomach ulcers so it is masked by an ester

Question 16

Palmitate ester is a prodrug for chloramphenicol. True or false?

Answer 16

True - used to reduce hydrophobicity