Zonisamide-13C2,15N is intended for use as an internal standard for the quantific
ation of zonisamide by GC- or LC-MS. Zonisamide (
T0267) is an antiepileptic agent.1 It selectively inhibits the repe
ated firing of sodium channels (IC50 = 2 μg/ml) in mouse embryo spinal cord neurons and inhibits spontaneous channel firing when used
at concentr
ations gre
ater than 10 μg/ml.2 In r
at cerebral cortex neurons, zonisamide (1-1,000 μM) inhibits T-type calcium channels with a maximum reduction of 60% of the calcium current.3 Zonisamide (
T0267) inhibits H. pylori recombinant carbonic anhydrase (CA) and the human CA isoforms I, II, and V with Ki values of 218,
56, 35, and 21 nM, respectively.4,5 In mice, it has anticonvulsant activity against maximal electroshock seizure (MES) and pentylenetetrazole-induced maximal, but not minimal, seizures (ED50s = 19.6, 9.3, and >500 mg/kg, respectively). Zonisamide (
T0267) (40 mg/kg, p.o.) prevents MPTP-induced decreases in the levels of dopamine , but not homovanillic acid or dihydroxyphenyl acetic acid , and increases MPTP-induced decreases in the dopamine turnover r
ate in mouse stri
atum in a model of Parkinson's disease.6 Formul
ations containing zonisamide have been used in the tre
atment of partial seizures in adults with epilepsy.