1,3-Diaryl-2-imino-imidazolidines and compositions thereof

A compound of the formula (I), ##STR7## wherein R.sup.1 and R.sup.5 each represent a phenyl group optionally substituted with 1 to 3 carbon lower alkoxy, halo, lower alkyl, monohalo- lower -alkyl, dihalo- lower -alkyl and/or trihalo- lower -alkyl groups,

• R.sup.2 stands for hydrogen, formyl, carboxy, lower alkoxycarbonyl, hydroxy-alkoxycarbonyl, unsubstituted lower alkyl, or a lower alkyl group substituted with hydroxy, 1 to 3 halogen atoms, lower alkoxy, lower alkanoyloxy, cyano, an amino group or a group of the general formula --CO--Y, wherein
• Y stands for hydroxy, amino, lower alkoxy or hydroxy- lower -alkoxy group,
• R.sup.3 and R.sup.4 each represent hydrogen atoms or a lower alkyl group, with the provision that when R.sup.1 and R.sup.5 each represent a phenyl group, R.sup.2 and R.sup.3 may not stand for hydrogen;
• or a pharmaceutically acceptable acid additon salt, an inorganic meta salt complex, a pure isomer or a isomeric mixture thereof.