Phenytoin-d10 (Synonyms: 5,5-Diphenylhydantoin-d10)

Phenytoin-d₁₀ is intended for use as an internal standard for the quantification of phenytoin by GC- or LC-MS. Phenytoin is an anticonvulsant agent and active metabolite of fosphenytoin . Phenytoin is formed from fosphenytoin by tissue phosphatases.¹ It inhibits neuronal voltage-gated sodium channels in a voltage-dependent manner.² Phenytoin reduces the neuronal firing frequency and decreases the amplitude of excitatory post-synaptic potentials (EPSPs) in electrically stimulated rat corticostriatal slices (EC₅₀s = 42.8 and 33.5 µM, respectively).³ It protects against seizures induced by maximal electroshock (MES) in mice (ED₅₀ = 10 mg/kg).⁴ Formulations containing phenytoin have been used in the treatment of tonic-clonic seizures and status epilepticus.

1.Boucher, B.A.Fosphenytoin: A novel phenytoin prodrugPharmacotherapy16(5)777-791(1996) 2.Yaari, Y., Selzer, M.E., and Pincus, J.H.Phenytoin: Mechanisms of its anticonvulsant actionAnn. Neurol.20(2)171-184(1986) 3.Calabresi, P., Centonze, D., Marfia, G.A., et al.An in vitro electrophysiological study on the effects of phenytoin, lamotrigine and gabapentin on striatal neuronsBr. J. Pharmacol.126(3)689-696(1999) 4.Brouillette, W.J., Jestkov, V.P., Akhtar, M.S., et al.Bicyclic hydantoins with a bridgehead nitrogen. Comparison of anticonvulsant activities with binding to the neuronal voltage-dependent sodium channelJ. Med. Chem.37(20)3289-3293(1994)