Stiripentol

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.

Signaling Pathways >> Metabolic Enzyme/Protease >> Cytochrome P450

Research Areas >> Neurological Disease

IC50: 1.58 μM (CYP3A4), 3.29 μM (CYP2C19)[1] Ki: 1.59±0.07μM (CYP3A4), 0.516±0.065 μM (CYP2C19)[1]

Stiripentol (STP) is an anticonvulsant agent, which can inhibit N-demethylation of CLB to N-desmethylclobazam (NCLB) mediated by CYP3A4 (noncompetitively) and CYP2C19 (competitively). The inhibition of CLB demethylation by Stiripentol (STP) is best described by a noncompetitive inhibition model with apparent Ki=1.6 μM for the cDNA-expressing CYP3A4 and by a competitive inhibition model with Ki=0.52 μM for the cDNA-expressing CYP2C19. Formation of OH-NCLB from NCLB by cDNA-expressing CYP2C19 is competitively inhibited by Stiripentol (STP) with a Ki=0.14 μM[1].

In mice treating with Stiripentol (STP) monotherapy, the difference between BT1 (39.67±1.09°C) and BT2 (41.32±1.05°C) reaches statistical significance (t=3.097, p<0.05). The difference in BT2 between Stiripentol (STP) monotherapy and CLB monotherapy is statistically significant (t=2.615, p<0.05). In mice treating with Stiripentol (STP)+CLB combination therapy, the difference between BT1 (40.18±0.58°C) and BT2 (43.03±0.49°C) reaches statistical significance (t=10.44, p<0.01)[2].

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)[1].

Two age groups, p1M (n=18, age 4 weeks) and p5M (n=18, age 5-10 months), of Scn1aRX/+ mice are assigned in this experiment. Both groups are divided randomly into three subgroups (n=6), and each subgroup is administered Stiripentol (STP) (300 mg/kg) alone, CLB (6.62 mg/kg) alone, or a combination of Stiripentol (STP) (p1M; 150 mg/kg, p5M; 300 mg/kg) and CLB (6.62 mg/kg). All drugs are administered by intraperitoneal injection (i.p.) after a 48-h recovery from baseline seizure study. Blood samples are collected at 1 h and 20 min after administration of CLB or STP+CLB for measurement of plasma concentrations of CLB and N-desmethylclobazam, respectively[2].

[1]. Giraud C, et al. In vitro and in vivo inhibitory effect of stiripentol on clobazam metabolism.Drug Metab Dispos. 2006 Apr;34(4):608-11. Epub 2006 Jan 13.

[2]. Cao D, et al. Efficacy of stiripentol in hyperthermia-induced seizures in a mouse model of Dravet syndrome. Epilepsia. 2012 Jul;53(7):1140-5.

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DATA ITEMS CITED :

6

MOLECULAR FORMULA :

C14-H18-O3

MOLECULAR WEIGHT :

234.32

WISWESSER LINE NOTATION :

T56 BO DO CHJ G1U1YQX1&1&1

HEALTH HAZARD DATA

ACUTE TOXICITY DATA

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

>3 gm/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

ARZNAD Arzneimittel-Forschung. Drug Research. (Editio Cantor Verlag, Postfach 1255, W-7960 Aulendorf, Fed. Rep. Ger.) V.1- 1951- Volume(issue)/page/year: 34,199,1984

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

1471 mg/kg

TOXIC EFFECTS :

Behavioral - anticonvulsant

REFERENCE :

ARZNAD Arzneimittel-Forschung. Drug Research. (Editio Cantor Verlag, Postfach 1255, W-7960 Aulendorf, Fed. Rep. Ger.) V.1- 1951- Volume(issue)/page/year: 34,199,1984

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

>5 gm/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

ARZNAD Arzneimittel-Forschung. Drug Research. (Editio Cantor Verlag, Postfach 1255, W-7960 Aulendorf, Fed. Rep. Ger.) V.1- 1951- Volume(issue)/page/year: 34,199,1984

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

1250 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

EJMCA5 European Journal of Medicinal Chemistry--Chimie Therapeutique. (Editions Scientifiques Elsevier, 29 rue Buffon, F-75005, Paris, France) V.9- 1974- Volume(issue)/page/year: 13,41,1978

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

72 mg/kg

TOXIC EFFECTS :

Behavioral - anticonvulsant

REFERENCE :

ARZNAD Arzneimittel-Forschung. Drug Research. (Editio Cantor Verlag, Postfach 1255, W-7960 Aulendorf, Fed. Rep. Ger.) V.1- 1951- Volume(issue)/page/year: 34,199,1984 ** REPRODUCTIVE DATA **

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

6400 mg/kg

SEX/DURATION :

female 2 week(s) pre-mating - 18 day(s) after conception

TOXIC EFFECTS :

Reproductive - Specific Developmental Abnormalities - craniofacial (including nose and tongue) Reproductive - Specific Developmental Abnormalities - musculoskeletal system

REFERENCE :

REPTED Reproductive Toxicology. (Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, NY 10523) V.1- 1987- Volume(issue)/page/year: 7,439,1993