Differences between eccentric and rotary tablet machines in the evaluation of powder densification behaviour

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• 作者：Palmieri ; Giovanni F. ; Joiris ; Etienne ; Bonacucina ; Giulia ; Cespi ; Marco ; Mercuri ; Annalisa
• 关键词：Compression ; Compaction ; Tableting ; Mechanical properties ; Rotary tablet machine ; Densification ; Heckel ; Stress ; Strain
• 刊名：International Journal of Pharmaceutics
• 出版年：2005
• 期刊代码：24_03785173
• 类别：pha
• 出版时间：July 14, 2005
• 卷：298
• 期：1
• 页码：164-175
• 文件大小：321 K

摘要

Differences in the dynamics of powder densification between eccentric and rotary machine were pointed out by compressing at different compression pressures microcrystalline cellulose, lactose monohydrate and dicalcium phosphate dihydrate and recovering the corresponding stress/strain data in both machines equipped to monitor punches displacement and compression forces. Heckel plots were then obtained from these stress/strain data.

Curves obtained in the rotary machine possess a narrower zone of linearity for the calculation of P_Y and D_A. The effect of the different compression mechanism of the rotary machine on the shape of the Heckel plot is more noticeable in a non-deforming material such as dicalcium phosphate. The effect of the longer dwell time of the rotary machine on the porosity reduction occurring after the maximum pressure has been reached, is more noticeable in a ductile material such as microcrystalline cellulose.

Heckel parameters obtained in the rotary press are in some cases different from those recovered in the eccentric machine because of the longer dwell time, machine deflection and punch tilting occurring in the rotary machine, although theoretically they could better describe the material densification in a high speed production rotary machine.