fgc5

Question 1

How can ester hydrolysis be detrimental to a drug’s pharmacological action? (Example: Methylphenidate)

Answer 1

Hydrolysis of the ester in methylphenidate (Ritalin) converts it into ritalinic acid, an inactive metabolite. This reduces its therapeutic effects and shortens the drug’s duration of action.

Question 2

How can ester hydrolysis be beneficial to drug pharmacology? (Example: Diphenoxylate)

Answer 2

Diphenoxylate is a prodrug that undergoes ester hydrolysis in the body to form diphenoxylic acid, which is the active form responsible for its antidiarrheal effect.

Question 3

How does ester hydrolysis benefit the administration of drugs? (Example: Aspirin)

Answer 3

Aspirin (acetylsalicylic acid) is absorbed in its ester form but hydrolyzes in the body to salicylic acid, which provides its anti-inflammatory and pain-relieving effects. The ester form helps with oral bioavailability.

Question 4

How does ester hydrolysis influence drug stability and storage? (Example: Aspirin)

Answer 4

Aspirin hydrolyzes over time, especially in humid conditions, forming salicylic acid and acetic acid. This reduces its effectiveness, making proper storage (cool, dry conditions) essential.

Question 5

What is the mechanism of amide bond hydrolysis?

Answer 5

Protonation (acidic conditions) or hydroxide attack (basic conditions) activates the amide bond. Nucleophilic attack on the carbonyl carbon forms a tetrahedral intermediate. Breakdown of the intermediate releases an amine (-NH₂) and a carboxylate (-COO⁻) or carboxylic acid (-COOH).