PURPOSE: To prepare the subject readily soluble crystals for a therapeutic agent which comprises a specific (tetrazol-5-yl)biphenyl-4-ylpyrazolo[1,2,4]triazole metal salt and has antagonistic action on angiotensin.

CONSTITUTION: 2,7-Diethyl-5-[[2'-(tetrazol-5-yl)biphenl-4-yl]methyl]-5H- pyrazolo[1,5-b][1,2,4]triazole and potassium are heated in methanol under stirring until the solids dissolve in. Then, the solvent is distilled off under reduced pressure and the residue is dissolved in isopropanol and hot-filtered. The solvent is distilled off from the filtrate under reduced pressure and the residue is combined with water and ethyl acetate and the crystals precipitated are filtered and dried under reduced pressure to give 2,7-diethyl-5-[[2'-(tetrazol-5-yl) biphenyl-4-yl]methyl]-5H-pyrazolo--[1,5-b][1,2,4] triazole potassium salt monohydrate.