3-Methyl-1-phenyl-2-pyrazolin-5-one drug substance analysis method, treatment of amyotrophic lateral sclerosis and suppression of progression of amyotrophic lateral sclerosis, and 3-methyl-1- Method for producing a drug containing a phenyl-2-pyrazolin-5-one drug substance

摘要

The method for analyzing the phenylhydrazine content in the 3-methyl-1-phenyl-2-pyrazolin-5-one drug substance comprises phenylhydrazine or a salt thereof, a first acidic water and a first water-soluble organic solvent, and is 0. To obtain the first measurement value by measuring the phenylhydrazine content of a standard solution showing a phenylhydrazine concentration of 0.01 μg / mL to 10 μg / mL, 3-methyl-1-phenyl-2-pyrazolin-5-one drug substance. , The phenylhydrazine content of the sample solution containing the second acidic water and the second water-soluble organic solvent is measured to obtain the second measured value, and the 3-methyl from the first measured value and the second measured value. -1-Phenyl-2-pyrazolin-5-one Including detecting the phenylhydrazine content in the drug substance, the first acidic water is at least one selected from hydrochloric acid, aqueous acetic acid, etc. The water-soluble organic solvent is at least one selected from acetonitrile and methanol, the second acidic water is at least one selected from hydrochloric acid, an aqueous acetic acid solution, and the like, and the second water-soluble organic solvent is selected from acetonitrile and methanol. At least one kind to be done.