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Details

Stereochemistry ABSOLUTE
Molecular Formula C12H14N2O2
Molecular Weight 218.2518
Optical Activity UNSPECIFIED
Defined Stereocenters 1 / 1
E/Z Centers 0
Charge 0

SHOW SMILES / InChI
Structure of MEPHENYTOIN, (+)-

SMILES

CC[C@]1(NC(=O)N(C)C1=O)C2=CC=CC=C2

InChI

InChIKey=GMHKMTDVRCWUDX-LBPRGKRZSA-N
InChI=1S/C12H14N2O2/c1-3-12(9-7-5-4-6-8-9)10(15)14(2)11(16)13-12/h4-8H,3H2,1-2H3,(H,13,16)/t12-/m0/s1

HIDE SMILES / InChI

Molecular Formula C12H14N2O2
Molecular Weight 218.2518
Charge 0
Count
Stereochemistry ABSOLUTE
Additional Stereochemistry
Defined Stereocenters 1 / 1
E/Z Centers 0
Optical Activity UNSPECIFIED

Description

Mephenytoin, (+)- is an (S)-enantiomer of anticonvulsant drug mephenytoin. Mephenytoin is usually administrated as a 1:1 racemic mixture of the (R)- and (S)-enantiomers. The marked stereoselectivity of 4’-hydroxylation of the phenyl ring of S-mephenytoin together with the relatively slow N-demethylation to R-PEH (R-5-phenyl-5-ethylhydantom) and even slower renal clearance results in a dramatic difference in the pharmacokinetic disposition of the S- and R-enantiomers of mephenytoin in man. As a consequence, S-mephenytoin provides a negligible contribution to circulating hydantoins, whereas R-mephenytoin is converted to the pharmacologically active demethylated product R-PEH which is the major circulating hydantoin during chronic administration of the racemic drug. Only the 4’-hydroxylation of the (S)-mephenytoin is absent in patents who are poor metabolizers of mephenytoin. It is not clear as to the clinical consequences of the accumulation of (S)-mephenytoin for the poor metabolizer phenotype. Indeed, it may be the extensive metabolizer who is at great risk of adverse effects by the formation of potentially toxic oxidative metabolites of (S)-mephenytoin.

Approval Year

Targets

Targets

Primary TargetPharmacologyConditionPotency
PubMed

PubMed

TitleDatePubMed
Stereoselective metabolism and disposition of the enantiomers of mephenytoin during chronic oral administration of the racemic drug in man.
1982 Jun
Cytochrome P-450 human-2 (P-450IIC9) in mephenytoin hydroxylation polymorphism in human livers: differences in substrate and stereoselectivities among microheterogeneous P-450IIC species expressed in yeasts.
1991 May
Species differences in stereoselective metabolism of mephenytoin by cytochrome P450 (CYP2C and CYP3A).
1993 Jan
Stereoselective disposition of mianserin is related to debrisoquin hydroxylation polymorphism.
1994 Aug
Evidence that CYP2C19 is the major (S)-mephenytoin 4'-hydroxylase in humans.
1994 Feb 22
Patents

Sample Use Guides

In Vitro Use Guide
The 4-hydroxylase activity of R-mephobarbital showed a high correlation (r = 0.985, p<0.001) with the 4'-hydroxylase activity of S-mephenytoin in a panel of nine human liver microsomes. R-Mephobarbital competitively inhibited S-mephenytoin 4'-hydroxylase activity (K(i) = 34 uM), while S-mephenytoin inhibited R-mephobarbital 4-hydroxylase activity (K(i) = 103 uM).
Substance Class Chemical
Created
by admin
on Tue Oct 22 14:50:38 UTC 2019
Edited
by admin
on Tue Oct 22 14:50:38 UTC 2019
Record UNII
D9818430MW
Record Status Validated (UNII)
Record Version
  • Download
Name Type Language
MEPHENYTOIN, (+)-
Common Name English
(+)-MESANTOIN
Common Name English
(+)-S-MEPHENYTOIN
Common Name English
D-MEPHENYTOIN
Common Name English
MEPHENYTOIN, (S)-
Common Name English
(+)-MEPHENYTOIN
Common Name English
(+)-5-ETHYL-3-METHYL-5-PHENYLHYDANTOIN
Systematic Name English
2,4-IMIDAZOLIDINEDIONE, 5-ETHYL-3-METHYL-5-PHENYL-, (5S)-
Systematic Name English
S-MEPHENYTOIN
Common Name English
Code System Code Type Description
PUBCHEM
107921
Created by admin on Tue Oct 22 14:50:38 UTC 2019 , Edited by admin on Tue Oct 22 14:50:38 UTC 2019
PRIMARY
CAS
70989-04-7
Created by admin on Tue Oct 22 14:50:38 UTC 2019 , Edited by admin on Tue Oct 22 14:50:38 UTC 2019
PRIMARY
EPA CompTox
70989-04-7
Created by admin on Tue Oct 22 14:50:38 UTC 2019 , Edited by admin on Tue Oct 22 14:50:38 UTC 2019
PRIMARY
Related Record Type Details
METABOLIC ENZYME -> SUBSTRATE
METABOLIC ENZYME -> SUBSTRATE