[PROBLEMS] Conventional can be manufactured in a simpler manner than has high bioavailability and higher dissolution properties even at low stomach acids further dissolution properties after a certain period of standing can be ensured, to provide an oral solid preparation, and it is to provide a simple manufacturing process for producing the oral solid preparation. A formed by grinding the hydrate crystals of aripiprazole as an active ingredient finely ground crystals, and an oral solid preparation comprising a pharmaceutically acceptable carrier, the average particle size of the milled crystals 15 m or less In a solid oral formulation is an oral solid preparation comprising an effective finely ground powder formed by pulverizing the anhydrous crystals with high hygroscopic aripiprazole as a component, and a pharmaceutically acceptable carrier, the average fine ground powder Oral solid preparations particle size of 10 m or less, (1) was pulverized hydrate crystals of aripiprazole, a process having an average particle diameter get the following milling crystals 15 m, (2) and the finely ground crystals obtained, pharmaceutical method of manufacturing an oral solid preparation comprising a step of mixing an acceptable carrier, and (1 ) a hygroscopic anhydrous aripiprazole crystals was ground, the step of an average particle size obtained finely pulverized powder following 10 m , (2 ) and the pulverized powder thus obtained, a method of manufacturing an oral solid preparation comprising a step of mixing a pharmaceutically acceptable carrier.BACKGROUND.【課題】従来よりも簡易な方法で製造でき、低胃酸者でも高い生体利用度及び高い溶出性を有し、さらに、一定期間放置後の溶出性も確保できる、経口固形製剤を提供すること、及びその経口固形製剤を製造する簡易な製造方法を提供することである。【解決手段】有効成分としてアリピプラゾールの水和物結晶を粉砕してなる微粉砕結晶、及び薬学的に許容される担体とを含む経口固形製剤であって、微粉砕結晶の平均粒子径が15μm以下である経口固形製剤、有効成分として吸湿性の高いアリピプラゾールの無水物結晶を粉砕してなる微粉砕粉末、及び薬学的に許容される担体とを含む経口固形製剤であって、微粉砕粉末の平均粒子径が10μm以下である経口固形製剤、(1)アリピプラゾールの水和物結晶を粉砕し、平均粒子径が15μm以下の微粉砕結晶を得る工程、(2)得られた微粉砕結晶と、薬学的に許容される担体を混合する工程を含む経口固形製剤の製造方法、並びに(1’)吸湿性の高いアリピプラゾールの無水物結晶を
