| 摘要 |
PROBLEM TO BE SOLVED: To obtain ascorbic acid particles remarkably improved in flowability and packability and suitable for a direct tabletting method not using an additive by applying a spherical crystallization method to ascorbic acid powder. SOLUTION: The particles are obtained by dissolving ascorbic acid powder in a good solvent (especially preferably water) and subsequently dropping the solution in a poor solvent at a lower temperature than that of the good solvent with stirring. The poor solvent is preferably a solvent having a solubility parameter (Mpa<1/2> ) comprising aδd of 15-17, aδp of 3-6 and aδh of 6-12, especially ethyl acetate, isopropyl acetate, etc. In the method, it is preferable to drop the solution in a 27-100 fold-volume of the poor solvent.
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