Richter Gedeon Vegyeszeti Gyar Rt

Andras Rado

Kalman Harsanyi

Bela Hegedus

Gyorgy Domany

Eva Againe Csongor

Janos Kreidl

Gyorgy Fekete

Lajos Toldy

Tibor Balogh

Jozsef Reiter

Endre Kasztreiner

Tibor Lang

Janos Borvendeg

Maria Farkas Nee Kirjak

Margit Bidlo Nee Igloy

Ida Deutsch Nee Juhasz

Bela Benke

Ferenc Morasz

Arpad Lazar

Hajnalka V Petho

Tibor Somogyi

Oszkar Fuchs

The invention relates to the new monohydrate of N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne (cimetidine), a histamine-H.sub.2 receptor antagonist which is called N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne H (cimetidine H) as well as to a process for the preparation of same, which comprises pouring a hot, homogeneous aqueous solution of N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne, optionally containing also methylamine, onto ice and separating the N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne monohydrate.

Cimetidine monohydrate

The invention relates to a new crystal modification of N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne (cimetidine), a histamine H-2 receptor antagonist having the Formula (I) ##STR1## as well as to a process for preparing same. In the description, this new modification is named N-methyl-N'-{2-[(5-methylimidazol-4-yl)-methylthio]-ethyl}-N'-cyanoguanidi ne Z (cimetidine Z).

Cimetidine Z, a new crystal modification of cimetidine

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Budapest, Hungary

Andras Rado