What is a liver S9 fraction?

A liver S9 fraction is a laboratory-prepared sample made from liver tissue and used to study how the liver processes drugs, chemicals, and other compounds. Think of it as a useful in vitro model of liver metabolism. It contains a mix of enzymes from both the microsomal and cytosolic parts of liver cells, allowing researchers to study several metabolic reactions in the same system.

The S9 fraction is prepared by gently breaking down liver tissue and separating its cellular components through centrifugation. Unlike isolated microsomes, which mainly represent the microsomal portion of the cell, the S9 fraction retains both microsomal and cytosolic enzymes. This gives researchers a broader view of how a compound may be metabolized.

S9 fractions support both Phase I and Phase II metabolic reactions. Researchers evaluate oxidation and reduction in Phase I reactions. While in Phase II reactions, conjugation pathways of the compounds are identified.

Researchers commonly use liver S9 fractions in drug discovery, ADME profiling, testing metabolic stability, metabolite identification, and toxicology research. They can also be prepared from different species, including human, beagle, rat, and mouse liver, depending on the objectives of the study.

Human liver S9 fractions help researchers understand how a drug candidate might be metabolized in humans before moving further through development. Liver S9 fraction gives researchers a convenient way to study liver metabolism in the laboratory, helping generate useful information about how a compound may be transformed in the body.