Jackson S, Sinka I C, Cocks A C F
Department of Engineering, University of Leicester, Leicester, UK.
Eur J Pharm Biopharm. 2007 Feb;65(2):253-6. doi: 10.1016/j.ejpb.2006.10.008. Epub 2006 Oct 20.
Die fill on a rotary tablet press involves complex powder flow phenomena. Conventional techniques for measuring flowability do not normally provide information that is directly relevant to the design of powder feed systems or to the selection of press parameters for the die filling process. Sinka et al. [I.C. Sinka, L.C.R. Schneider, A.C.F. Cocks, Measurement of the flow properties of powders with special reference to die fill, in: International Journal of Pharmaceutics 280 (1-2) (2004) 27-38] used an experimental shoe-die system to characterise the flow behaviour of pharmaceutical powders. A rigorous data analysis procedure was developed by Schneider et al. [L.C.R. Schneider, I.C. Sinka, A.C.F. Cocks, Characterisation of the flow behaviour of pharmaceutical powders using a model die-shoe filling system, in: Powder Technology (in press)] to evaluate the experimental results, however, when scaling the results to a rotary tablet press, the die fill efficiency was underpredicted by a factor of approximately 2, because the experimental system did not capture major features of the rotary press flow process. The suction effect, whereby the lower punch is moved downwards while the top of the die is exposed to powder in the feed system, is a key element of the process. In this note we describe the development of a model shoe-die system that allows the effect of suction to be investigated. The results demonstrate the improvement offered by suction and illustrate how a fundamental understanding of die fill phenomena could assist the selection of process parameters to maximise the operational speed of a rotary press.
旋转式压片机的模孔填充涉及复杂的粉末流动现象。传统的测量流动性的技术通常无法提供与粉末进料系统设计或模孔填充过程中压片参数选择直接相关的信息。辛卡等人[I.C. 辛卡、L.C.R. 施耐德、A.C.F. 科克斯，特别参考模孔填充对粉末流动特性的测量，载于《国际药剂学杂志》280(1 - 2)(2004)27 - 38]使用了一个实验性的靴形 - 模孔系统来表征药用粉末的流动行为。施耐德等人[L.C.R. 施耐德、I.C. 辛卡、A.C.F. 科克斯，使用模型靴形 - 模孔填充系统表征药用粉末的流动行为，载于《粉末技术》(即将出版)]开发了一种严格的数据分析程序来评估实验结果，然而，当将结果按比例放大到旋转式压片机时，模孔填充效率被低估了约2倍，因为实验系统没有捕捉到旋转式压片机流动过程的主要特征。抽吸效应，即下冲头向下移动而模孔顶部暴露于进料系统中的粉末时产生的效应，是该过程的一个关键要素。在本说明中，我们描述了一种模型靴形 - 模孔系统的开发，该系统能够研究抽吸效应。结果证明了抽吸效应带来的改进，并说明了对模孔填充现象的基本理解如何有助于选择工艺参数以最大化旋转式压片机的运行速度。
