Sparingly soluble active pharmaceutical intermediate with improved solubility and stability, and method for producing the same

PROBLEM TO BE SOLVED: To provide a sparingly soluble active pharmaceutical intermediate with improved solubility and stability, especially in candesartan cilexetil, Form I crystalline powder of candesartan cilexetil, whose particle size is relatively small and contains essentially no particles having a particle size of 100 μm or more (high solubility), and which shows little increase in the amount of desethyl compound (high stability) and has high purity, and to provide a simple method for producing the same.SOLUTION: The fine particle powder of sparingly soluble active pharmaceutical intermediate of the present invention is produced by a production method comprising: a step of feeding powder containing large particles having a desired crystal form; and a pulverization step of obtaining the small particle powder containing essentially no particles having a particle size of 100 μm or more, which inhibit improvement of solubility, by pulverizing the powder containing large particles with a work volume such that, when D90 of the powder containing large particles is denoted by D1 (m) and D90 of the small particle powder by D2 (m), a value of {(1/D2)-(1/D1)} is 10 to 50 (1/m).SELECTED DRAWING: None