What happens in Phase 1 of drug metabolism?

Phase I metabolism consists of reduction, oxidation, or hydrolysis reactions. These reactions serve to convert lipophilic drugs into more polar molecules by adding or exposing a polar functional group such as -NH2 or -OH.

What is drug metabolism explain Phase I reaction?

Phase I biotransformation reactions introduce or expose functional groups on the drug with the goal of increasing the polarity of the compound. As most small molecule drugs are lipophilic in nature, drug metabolism converts these hydrophobic compounds into more water soluble compounds that can be excreted.

What are the phases of drug metabolism?

Drugs can be metabolized by oxidation, reduction, hydrolysis, hydration, conjugation, condensation, or isomerization; whatever the process, the goal is to make the drug easier to excrete. The enzymes involved in metabolism are present in many tissues but generally are more concentrated in the liver.

What step in Phase I drug metabolism do the cytochromes P450 perform?

In phase I, enzymes such as cytochrome P450 oxidases introduce reactive or polar groups into xenobiotics. These modified compounds are then conjugated to polar compounds in phase II reactions. Drug metabolism often converts lipophilic compounds into hydrophilic products that are more readily excreted.

What are the two categories of drug metabolism?

There are often two phases of drug metabolism. Phase I: Non-synthetic reactions such as cleavage (e.g. oxidation, reduction, hydrolysis), formation or modification of a function group. Phase II: Synthetic reactions such as conjugation with an endogenous substance (e.g. sulfate, glycine, glucuronic acid).

What are the sites of drug metabolism?

Most drugs must pass through the liver, which is the primary site for drug metabolism. Once in the liver, enzymes convert prodrugs to active metabolites or convert active drugs to inactive forms. The liver’s primary mechanism for metabolizing drugs is via a specific group of cytochrome P-450 enzymes.

What is the purpose of phase 2 metabolism?

Phase II reactions involve conjugation by coupling the drug or its metabolites to another molecule, such as glucuronidation, acylation, sulfate, or glicine. The substances that result from metabolism may be inactive, or they may be similar to or different from the original drug in therapeutic activity or toxicity.

What is the main purpose of drug metabolism?

The primary objective of drug metabolism is to facilitate a drug’s excretion by increasing its water solubility (hydrophilicity).

What is the purpose of drug metabolism?

The majority of metabolic processes that involve drugs occur in the liver, as the enzymes that facilitate the reactions are concentrated there. The purpose of metabolism in the body is usually to change the chemical structure of the substance, to increase the ease with which it can be excreted from the body.