solubility: chemical modification + effect of pH

Question 1

How can the solubility of a drug be manipulated?

Answer 1

1) selecting correct solvent (use of co-solvents)
2) formation of a salt
3) addition of solubilising groups to structure
4) using effect of pH
5) using special dosage forms

Question 2

What must be considered when incorporating water-solubilising groups?

Answer 2

1) type of group added
2) whether the reaction is reversible/irreversible
3) chemical route of introduction

Question 3

What does adding polar groups do?

Answer 3

enhances solubility of parent compound in water

Question 4

Give some examples of more polar groups.

Answer 4

1) alcohols
2) amines
3) amides
4) carboxylic acids
5) sulphonic acids
6) phosphorus oxyacids

Question 5

Give some examples of less polar groups.

Answer 5

1) ethers
2) aldehydes
3) ketones
4) esters

Question 6

in vivo

Answer 6

in a living organism

Question 7

What groups are likely to be irreversibly attached?

Answer 7

1) C-C
2) C-O
3) C-N

Question 8

What groups are likely to be metabolised in vivo?

Answer 8

groups that are linked by:

1) esters
2) amides
3) phosphates
4) sulphates

Question 9

prodrug

Answer 9

biologically inactive compound which can be metabolised in vivo to produce a drug

Question 10

azo bond

Answer 10

N=N

Question 11

When can water solubilising groups be introduced in the synthesis?

Answer 11

at any stage

Question 12

What is the general formula of acetate esters?

Answer 12

CH₃CO₂R

Question 13

How can the degree of ionisation be determined?

Answer 13

Henderson-Hasselbalch equation

Question 14

pKₐ =

Answer 14

1) - log₁₀Kₐ

2) pH + log₁₀ [HA]/[A⁻]

Question 15

pH =

Answer 15

• log₁₀ [H⁺]

Question 16

B + H⁺ ⇌

Answer 16

BH⁺