Puckhaber Daniel, Eichler Sebastian, Kwade Arno, Finke Jan Henrik
Institute for Particle Technology, Technische Universität Braunschweig, Volkmaroder Str. 5, 38104 Braunschweig, Germany.
Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, Franz-Liszt-Str. 35A, 38106 Braunschweig, Germany.
Pharmaceutics. 2020 Mar 21;12(3):283. doi: 10.3390/pharmaceutics12030283.
Paddle feeders are devices commonly used in rotary tablet presses to facilitate constant and efficient die filling. Adversely, the shear stress applied by the rotating paddles is known to affect the bulk properties of the processed powder dependent on the residence time. This study focuses on the residence time distribution (RTD) of two commonly applied excipients (microcrystalline cellulose, MCC; dicalcium phosphate, DCP), which exhibit different flow properties inside rotary tablet presses. To realistically depict the powder flow inside rotary tablet presses, custom-made tracer powder was developed. The applied method was proven to be appropriate as the tracer and bulk powder showed comparable properties. The RTDs of both materials were examined in two differently scaled rotary tablet presses and the influence of process parameters was determined. To analyze RTDs independent of the mass flow, the normalized variance was used to quantify intermixing. Substantial differences between both materials and tablet presses were found. Broader RTDs were measured for the poorer flowing MCC as well as for the production scale press. The obtained results can be used to improve the general understanding of powder flow inside rotary tablet presses and amplify scale-up and continuous production process development.
桨式加料器是旋转式压片机中常用的装置，用于实现持续高效的模孔填充。然而，已知旋转桨叶施加的剪切应力会根据停留时间影响加工粉末的堆积特性。本研究聚焦于两种常用辅料（微晶纤维素，MCC；磷酸二钙，DCP）的停留时间分布（RTD），这两种辅料在旋转式压片机内表现出不同的流动特性。为了真实地描绘旋转式压片机内的粉末流动，研发了定制的示踪粉末。所采用的方法被证明是合适的，因为示踪剂和散装粉末表现出可比的特性。在两台不同规模的旋转式压片机中检测了两种物料的停留时间分布，并确定了工艺参数的影响。为了独立于质量流分析停留时间分布，使用归一化方差来量化混合程度。发现两种物料和压片机之间存在显著差异。流动性较差的微晶纤维素以及生产规模的压片机的停留时间分布更宽。所得结果可用于增进对旋转式压片机内粉末流动的总体理解，并促进放大生产和连续生产工艺的开发。
