Phase I Reactions: These involve functionalization reactions such as oxidation, reduction, and hydrolysis. The goal is to introduce or unmask a functional group on the drug molecule, enhancing its reactivity for the subsequent phase. Phase II Reactions: These are conjugation reactions where the drug or its phase I metabolite is combined with an endogenous substrate (like glucuronic acid, sulfate, or glycine) to form a more water-soluble compound that can be easily excreted.
