(S)-MEPHENYTOIN

Manufacturing Process

23 parts sodium was dissolved in 300 parts of ethanol and added to 160 parts of 5-phenylcyanacetamide in 750 parts of ethanol. A mixture was cooled straight away and a sodium salt of amide precipitated as a white powder. 200 parts of ethyl iodide was added to this mixture and heated for 1.5 hours. The ethanol was distilled off, water was added to the residue and rapidly hardened oil precipitated. After recrystallization from ethanol, 5-ethyl-5- phenylacetamide afforded; MP: 116°C.100 parts of sodium hydroxide was solved in 500 parts of water and added to 83 parts of bromine by cooling. 5-Ethyl-5-phenylacetamide was added to above prepared mixture. It dissolved quickly, whereupon all mass was heated some time, cooled and stood at room temperature some hours. Then a solution of sodium bisulfite was added before the formed precipitate dissolved. The reaction mixture was filtered, the filtrate was acidified to give rapidly hardened oil. After recrystallization from ethanol 5-ethyl-3-methyl-5-phenylhydantoin was yielded as the bright needles; MP: 201°-202°C.

Therapeutic Function

Anticonvulsant, Antiepileptic

Biological Activity

CYP2C19 substrate. Anticonvulsant.

Biochem/physiol Actions

CYP2B6 and CYP2C19 substrate; anticonvulsive, antiepileptic.

Safety Profile

Poison by ingestion and intraperitoneal routes. Human systemic effects by ingestion: somnolence, hemorrhage, changes in teeth and supporting structures. Human mutation data reported. An experimental teratogen. An FDA proprietary drug used as an anticonvulsant. When heated to decomposition it emits toxic fumes of NOx.

Brand name

Mesantoin (Novartis).