## Abstract

Although inaccurate true density affects analysis of powder compaction data, such effects have not been systematically evaluated in the literature. This work is aimed at quantitatively evaluating effects of inaccurate true density on tableting data analysis using the Ryshkewitch equation, σ = σ_{0} e^{-bε}, where ε is tablet porosity, σ is tensile strength, σ_{0} and b are constants that are used to characterize tableting properties of a powder. Mathematical expressions are derived to enable reliable prediction of the influence of inaccurate true density on σ_{0} and b. The validity of the expressions is suggested by modeling the effects of inaccurate true density based on a set of accurate literature tableting data and confirmed using multiple sets of tableting data of water-containing powders that exhibit inaccurate helium pycnometry densities. Percentage errors in fitted σ^{0} and b as functions of errors in true density follow the derived mathematical expressions. With increasing percentage error in true density, percentage errors increase exponentially in fitted σ_{0} and increase linearly in fitted b, while R^{2} is not affected. According to the mathematical expressions, true density with <0.28% error is required to achieve 4% accuracy in fitted σ_{0} for typical pharmaceutical powders.

Original language | English (US) |
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Pages (from-to) | 2061-2068 |

Number of pages | 8 |

Journal | Journal of Pharmaceutical Sciences |

Volume | 94 |

Issue number | 9 |

DOIs | |

State | Published - Sep 2005 |

## Keywords

- Data analysis
- Porosity
- Tableting
- Tensile strength
- The Ryshkewitch equation
- True density