A Novel Approach to Derive a Compression Parameter Indicating Effective Particle Deformability

Abstract

In this article, a compression parameter is derived and its physical significance discussed. Tablets were formed from two sodium chloride powders and from two sucrose powders over a wide range of compaction pressures and the tensile strength and the porosity of the tablets were determined. From these data, the novel compression parameter and the Heckel parameter were calculated. Above a lower pressure threshold, the tablet strength increased relatively linear with compaction pressure up to 300–500 MPa and thereafter, the tablet strength leveled off. From the linear region, the compression parameter was derived. The tablet porosity data obeyed reasonably the Heckel function and from the linear region, the yield strength was calculated. For all four powders, a ratio between the compression parameter and the Heckel yield strength of about 3 was obtained. It is concluded that the suggested compression parameter represents an indication of the effective deformability of particles during compression which is suggested to correlate with the hardness of the particles.

Keywords:

• Powder compactability
• Tablet tensile strength
• Compression parameter
• Effective deformability
• Yield strength
• Hardness

Acknowledgments

Financial support for this study was obtained from Pharmacia AB (Sweden). I thank Mrs. Gunilla Andersson for excellent experimental assistance. This study is a part of a research program in pharmaceutical materials science at Uppsala University.