trifluoromethylbenzoylguanidine hydrochloride and its hydrates processes for preparing this benzoylguanidine salt and its hydrates pharmaceutical compositions containing this benzoylguanidine salt and its hydrates and its use in treating diseases particularly those in which inhibition of the cellular na h exchange is of therapeutic benefit application_number US 44483706 A description it has been found that the abovementioned aim is achieved by means of the compound 4 4 2 pyrrolylcarbonyl 1 piperazinyl 3 trifluoromethylbenzoylguanidine hydrochloride 1 the compound of formula 1 is not hygroscopic and dissolves readily in physiologically acceptable solvents it is also characterized by a high degree of stability unlike the compound of formula 1 does not meet the requirements set out hereinbefore however accordingly in one aspect the present invention relates to the compound of formula 1 as such in another aspect the present invention relates to the compound of formula 1 in the form of its hydrates preferably in the form of its monohydrate or hemihydrate in another aspect the present invention relates to the use of the compound of formula 1 as a medicament the present invention further relates to the use of the compound of formula 1 optionally in the form of its hydrates for preparing a pharmaceutical composition for treating diseases in which inhibitors of the cellular na h exchange may develop a therapeutic benefit the present invention further relates to the use of the compound of formula 1 to prepare a pharmaceutical composition for treating cardiovascular diseases the present invention further relates to the use of the compound of formula 1 to prepare a pharmaceutical composition for treating arrhythmia such as occurs in hypoxia for example the present invention further relates to the use of the compound of formula 1 to prepare.