abstract bibtex

To characterize and develop a tableting process the compressibility (porosity vs compression stress), tabletability (tensile strength vs compression stress) and compactibility (tensile strength vs porosity) are commonly investigated as described e.g. in USP\textless1062\textgreater. In addition to these so called out of-die characteristics the in-die process can be analyzed using an instrumented tablet press with high resolution force–distance measuring system. With this approach specific energy values, elastic recovery and in-die compressibility data are obtained. Very common is the analysis of the porosity decrease with increasing compression stress in terms of the well-known Heckel plot. Analyzing the in-die compressibility of materials with low bulk modulus, apparent porosity values below zero were frequently observed at elevated compression stress but are rarely described and discussed in the literature. These observations can be handled in pragmatic ways as neglecting high compression stress data, “adjusting” the volume of the compact or assuming errors of the “true” density values used, which are frequently measured by gas-pycnometry.

@article{john_determination_nodate, title = {Determination of the solid (“true”) density of pharma- ceutical powders and the impact on tablet compression characterization}, abstract = {To characterize and develop a tableting process the compressibility (porosity vs compression stress), tabletability (tensile strength vs compression stress) and compactibility (tensile strength vs porosity) are commonly investigated as described e.g. in USP{\textless}1062{\textgreater}. In addition to these so called out of-die characteristics the in-die process can be analyzed using an instrumented tablet press with high resolution force–distance measuring system. With this approach specific energy values, elastic recovery and in-die compressibility data are obtained. Very common is the analysis of the porosity decrease with increasing compression stress in terms of the well-known Heckel plot. Analyzing the in-die compressibility of materials with low bulk modulus, apparent porosity values below zero were frequently observed at elevated compression stress but are rarely described and discussed in the literature. These observations can be handled in pragmatic ways as neglecting high compression stress data, “adjusting” the volume of the compact or assuming errors of the “true” density values used, which are frequently measured by gas-pycnometry.}, language = {en}, author = {John, E and Höltkemeier, T and Grandeury, A and Juhnke, M and Finke, J H and Wünsch, I and Kwade, A}, keywords = {Heckel plot, Stylcam, compactibility, compressibility, in-die process, powder density, tabletability}, pages = {18} }

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