All the following drugs are reversible inhibitors of COX EXCEPT-

Ans. is 'c' i.e., Aspirin o Aspirin inhibits COX irreversibly by acetylating one of its serine residues, return of COX activity depends on synthesis of fresh enzyme. Other NSAIDs are competitive and reversible inhibitors of COX, return of activity depends on their dissociation from the enzyme which in turn is governed by the pharmacokinetic characteristics of the compound.