A material-saving and robust approach for obtaining accurate out-of-die powder compressibility

• Published in: Powder technology Vol. 361; pp. 903 - 909
• Main Authors: Hirschberg, Cosima, Paul, Shubhajit, Rantanen, Jukka, Sun, Changquan Calvin
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.02.2020; Elsevier BV
• Subjects: Compaction; Compaction simulator; Compacts; Compressibility; Compressibility (powder); Elastic recovery; In-die; Material properties; Materials recovery; Out-of-die; Pressure; Pressure dependence; Tablet density; Tablet density; Compressibility; In-die; Elastic recovery; Out-of-die; Compaction simulator
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2019.11.004

Density is an important material property for evaluating, or developing a tablet formulation. In-die compressibility data can be obtained using a small amount of powder with the help of a compaction simulator. However, compacts undergo volume expansion upon ejection from die. Therefore, accurate out-of-die compressibility profiles cannot be directly obtained from the in-die data. By splitting the tablet elastic recovery into three components (in-die axial, out-of-die axial, radial), we have shown that the in-die elastic recovery is linearly dependent on the compaction pressure within the range investigated, and the out-of-die elastic recovery is a material constant. Hence, we have developed a two-step data treatment (the Hirschberg-Sun approach) for deriving an accurate out-of-die compressibility profile from in-die and out-of-die data of two tablets compressed at a low and a high compaction pressure. The broad applicability of the approach was verified with a larger number of diverse materials. [Display omitted] •In-die elastic recovery is linearly dependent on peak compaction pressure.•Out-of-die elastic recovery is a material constant.•The Hirschberg – Sun approach predicts an accurate compressibility profile from in-die data.•This material-sparing approach requires to make two tablets.•This approach is applicable for a large number of powders with different mechanical properties.