In vitro activity: Stiripentol (formerly known as BCX2600 and STP; trade name: Diacomit) is an anticonvulsant agent that inhibits the activity of several cytochromes P450 (P450s). Stiripentol inhibits N-demethylation of CLB to NCLB mediatated by CYP3A4 (noncompetitively) and CYP2C19 (competitively) with Ki of 1.59±0.07 and 0.516±0.065 μM and IC50 of 1.58 and 3.29 μM, respectively. In August 2018, FDA approved Stiripentol to treat seizures associated with Dravet syndrome in patients 2 years of age and older taking clobazam.

Kinase Assay: Stiripentol (STP) is an anticonvulsant agent, which can inhibit N-demethylation of CLB to NCLB mediatated by CYP3A4 (noncompetitively) and CYP2C19 (competitively) with Ki of 1.59±0.07 and 0.516±0.065 μM and IC50 of 1.58 and 3.29 μM, respectively.

Cell Assay: The inhibition constants (apparent Ki) of Stiripentol (STP) for CLB demethylation by CYP3A4 and CYP2C19 are determined using various concentrations of CLB (2, 10, 20, 40, 60, and 100 μM) with increasing concentrations of Stiripentol (STP) (0, 0.5, 1, 2, and 5 μM). Concerning NCLB hydroxylation by CYP2C19, the apparent Ki is similarly determined with different concentrations of NCLB (1.5, 4, 6, 8, 12, and 14 μM) and STP (0, 0.1, 0.5, 1, and 2 μM). IC50 values are determined by coincubation of the substrate at concentration in the range of the therapeutic plasma concentrations (2 μM CLB or 14 μM NCLB) with increasing concentrations of Stiripentol (STP) (0.001, 0.002, 0.005, 0.01, 0.05, 0.1, 0.25, 2, 5, and 10 μM).