Function of 38 variants CYP2C9 polymorphism on ketamine metabolism in vitro

Cytochrome P450 proteins (CYP 450) is the most important enzyme system of drug phase I metabolism in liver. In previous reports, reduced efficiency or increased risk of adverse events can be affected by primary sequence mutation in CYP450.

To investigate the effect of gene polymorphism on the metabolism of ketamine in vitro, including the new alleles: 2C9*58, *59 and *60.

Incubation system which was contained insect microsome, b5, NADPH and 1M PBS incubated 10 μM-1000 μM ketamine in 37 °C for 40 min concentration of norketamine was analyzed by ultra-performance liquid chromatography-tandem mass spectrometry system (UPLC-MS/MS).

Catalytic activity of thirty-eight CYP2C9 alleles on ketamine metabolism to norketamine was surveyed. Compared with 2C9*1, three alleles (2C9*40, *49 and *51) was demonstrated dramatically increased intrinsic clearance (1.2-fold-3.75-fold); four subtypes (2C9*27, *31, *41 and *56) exhibited no significantly change on enzyme activity. The resting 31 alleles expressed different degrees of reduction compared with wild type.

The result of research warns that attention should be more paid on individual who carry on the special 2C9 alleles under the situation of administrating ketamine.