A method for micronization of a dispersion of particles comprising a protein having a predetermined level of biological activity. The method comprises introducing the dispersion into a vortex chamber miiiing apparatus under milling conditions which result in a protein powder having a particle size distribution of 5 to 100 μm and/or exhibiting a 30 to 400 fold size reduction of the protein particle dispersion from its original size, and retaining at least 80% of the predetermined level of biological activity of the protein. The milling conditions include one or more parameters selected from the following: input pressure between 1 and 7 Bars； injector pressure between 0.2 and 5 Bars； loading rate between 0.1 and 5 kg/hour； and gas flow between 30 and 100 m3/hour.本發明係關於一種微粒化顆粒分散物之方法，該等顆粒包含具有預定生物活性量之蛋白質。該方法包含在產生具有5 μm至100 μm之粒度分布及/或展現蛋白質顆粒分散物在尺寸上自其原始尺寸減小30至400倍且保留蛋白質之預定生物活性量之至少80%的蛋白質粉末之研磨條件下向一渦流室研磨裝置中引入分散物。研磨條件包括一或多個選自以下各參數之參數：在1巴與7巴之間的輸入壓力；在0.2巴與5巴之間的注射器壓力；在0.1公斤/小時與5公斤/小時之間的裝載速率；及在30立方公尺/小時與100立方公尺/小時之間的氣流。
