examples illustrate the present invention but it is not limited to the examples mannitol 20 g was dissolved in distilled water and to the mixture was added the compound i 10 g to the mixture under stirring by a stirrer was added sodium hydroxide 0 44 g and thereto was added a distilled water to fill up to 500 ml to give a clear aqueous solution of ph 7 65 the aqueous solution prepared in example 1 a was sterilized by a conventional method filled in vials 5 ml portion each freeze dried by a conventional method to give 100 vials each containing 100 mg of the compound i to the mixture of ethanol 50 ml and water total approximately 120 ml were added the compound i 16 g and mannitol 14 g and to the mixture under stirring was added 1n aqueous solution of sodium hydroxide 20 ml corresponds to 800 mg little by little to the mixture was added water in order to fill up to 200 ml of total amount to give a clear solution of ph 8 05 the aqueous solution prepared in example 2 a was sterilized by a conventional method filled in vials 5 ml portion each and freeze dried by a conventional method to give 40 vials of freeze dried drug products each containing 400 mg of the compound i to the mixture of ethanol 66 ml and water total approximately 120 ml was added the compound i 20 g and mannitol 10 g and to the mixture under stirring was added 1n aqueous solution of sodium hydroxide 25 ml corresponds to 1 g little by little thereto was added water in order to.