4258. Fosphenytoin

Nomenclature

CAS number: 93390-81-9
5,5-Diphenyl-3-[(phosphonooxy)methyl]-2,4-imidazolidinedione; 3-(hydroxymethyl)-5,5-diphenylhydantoin phosphate ester; (3-phosphoryloxymethyl)phenytoin; prophenytoin.
C16H15N2O6P; mol wt 362.27.
C 53.05%, H 4.17%, N 7.73%, O 26.50%, P 8.55%.

Description and references

Prodrug of phenytoin, q.v. Prepn: V. J. Stella, K. B. Sloan, US 4260769 (1981 to INTERx). Series of articles on chemical properties and pharmacokinetics: S. A. Varia et al., J. Pharm. Sci. 73, 1068-1090 (1984). Pharmacology: R. D. Smith et al., Epilepsia 30, Suppl. 2, S15 (1989). Clinical bioavailablilty and pharmacokinetics: B. D. Jamerson et al., ibid. 31, 592 (1990). Series of articles on use in epilepsy: Neurology 46, Suppl. 1, S1-S28 (1996). Clinical trial in epilepsy and neurosurgery: B. J. Wilder et al., Arch. Neurol. 53, 764 (1996).

Chemical structure

Properties

White crystals from acetone, mp 173-176.5°.

Derivative

Disodium salt.

Nomenclature

CAS number: 92134-98-0
Fosphenytoin sodium; ACC-9653; Cerebyx (Pfizer); Pro-Epanutin (Pfizer).
C16H13N2Na2O6P; mol wt 406.24.
C 47.30%, H 3.23%, N 6.90%, Na 11.32%, O 23.63%, P 7.62%.

Properties

White crystals as the dihydrate from water-ethanol-acetone, mp 220° (softens). pH of a saturated aqueous soln: ≈9. Soly at 25° (mg/ml): 142 in water. LD50 in mice, rats (mg/kg): 234, 363 i.v. (Smith).

Therapeutic Category

Anticonvulsant.

Keywords

Anticonvulsant