Vial geometry for optimized mixing

A vial assembly includes a vial and a needle having at least one port. The vial includes particulate matter, a septum, a neck region including a first width, and a particulate region including a second width greater than the first width. The vial assembly is configured to move to a locked position. When in the locked position, the needle may be configured to pierce the septum with the at least one port configured to be located in the neck region. The at least one port may be configured to inject a fluid into the vial assembly to mix with particulate matter upon actuation of the vial engagement mechanism in a first direction and to receive the resulting mixed fluid from the vial assembly upon actuation of the vial engagement mechanism in a second direction opposite the first direction. 一种药瓶组件，包括药瓶和具有至少一个端口的针头。药瓶包括颗粒物质、隔膜、包括第一宽度的颈部区域和包括大于第一宽度的第二宽度的颗粒区域。药瓶组件配置成移动到锁定位置。当处于锁定位置时，针头可以配置成刺穿隔膜，其中所述至少一个端口配置成位于颈部区域中。所述至少一个端口可以配置成在沿着第一方向致动药瓶接合机构时将流体注入药瓶组件中以与颗粒物质混合以及在沿着与第一方向相反的第二方向致动药瓶接合机构时从药瓶组件接收所得到的混合流体。