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Effective Kawakita parameters for binary mixtures
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
2009 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 189, no 2, 270-275 p.Article in journal (Refereed) Published
Description
Abstract [en]

Despite the fact that many industrial processes use mixtures of powders   with different physical and mechanical properties, most fundamental   studies of powder compression have focused on single-component systems.   There is thus an obvious need for an improved understanding of the   compression behaviour of mixtures of particulate and granular solids.   In this contribution, we show that the Kawakita equation may be   particularly useful in this regard. The reason for this is that the   degree of compression (i.e., the ratio between the volume reduction and   the initial powder volume) for sufficiently high compression pressures   P is a linear function of I I P. For ideal mixtures, for which the   volume of each component may be determined independently of the others,   this linearity implies that effective Kawakita parameters for the   mixture may be readily expressed in terms of the parameters of its   components. In order to validate the proposed approach, binary mixtures   of mm-sized spherical agglomerates prepared by wet granulation followed   by extrusion and spheronization were investigated experimentally.   Predicted and measured Kawakita parameters were generally in good   agreement, indicating that the assumption of ideal mixing behaviour is   valid for this type of systems.

Place, publisher, year, edition, pages
2009. Vol. 189, no 2, 270-275 p.
Keyword [en]
Compression, Powder, Granular material, Mixture, Kawakita parameters
National Category
Pharmaceutical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-97467DOI: 10.1016/j.powtec.2008.04.016ISI: 000263866100017OAI: oai:DiVA.org:uu-97467DiVA: diva2:172428
Available from: 2008-09-09 Created: 2008-09-09 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Compression analysis as a tool for technical characterization and classification of pharmaceutical powders
Open this publication in new window or tab >>Compression analysis as a tool for technical characterization and classification of pharmaceutical powders
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There are today strong incentives for an increased understanding of material properties and manufacturing processes to facilitate the development of new technologies in the pharmaceutical industry. The purpose of this thesis was to suggest methods requiring a low sample amount for characterization of technical properties of powders.

Compression analysis was used to evaluate the formulation relevance of some compression equations. Using the mechanics of single granules to estimate powder functionality was part of this work. It was concluded that the formability of granular solids and the plasticity of single granules could be determined with compression analysis by using the Kawakita model for single components and binary mixtures of ductile granules.

Further on, the fragmentation propensity of solid particles could be estimated from compression analysis by using the Shapiro equation, enabling indicators of both the fragmentation and the deformation propensity of particles to be derived in one single compression test.

The interpretations of the compression parameters were only valid if the influence of particle rearrangement was negligible for the overall compression profile. An index indicating the extent of particle rearrangement was developed and a classification system of powders into groups dependent on the incidence of particle rearrangement was suggested as tools to enable rational interpretations of compression parameters.

The application of compression analysis was demonstrated by investigating the relevance of the mechanics of granular solids for their tableting abilities. The plasticity of single gran-ules was suggested to influence both the rate of compactibility and the mode of deformation, and consequently the maximal tablet strength. The degree of granule bed deformation was shown to be a potential in line process indicator to describe the tableting forming ability.

This thesis contributes to a scheme, suitable in formulation work and process control, to describe manufacturability of powders for an enhanced tablet formulation technology.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2008. 72 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 79
Keyword
compaction, compression, granules, Kawakita, mechanical properties, particles, PAT, pharmaceutical powders, tablets
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-9214 (URN)978-91-554-7265-8 (ISBN)
Public defence
2008-10-03, B21, Biomedical Center, BMC, Husargatan 3, Uppsala, 13:15
Opponent
Supervisors
Available from: 2008-09-09 Created: 2008-09-09Bibliographically approved

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Frenning, Göran

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