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Crystal Engineering and Particle Design for the Powder Compaction Process

1992; Taylor & Francis; Volume: 18; Issue: 6-7 Linguagem: Inglês

10.3109/03639049209058558

1520-5762

Peter York,

Powder Metallurgy Techniques and Materials

The historical background to the subject of crystal engineering of pharmaceuticals is briefly reviewed with reference to materials as diverse as insulin and direct compression tablet excipients. In the light of the limited scientific and practical information available on the topic two questions are posed -Is it possible to prepare 'designer' materials with preferred processing, specifically compressive, properties giving optimised product characteristics?How can such materials be efficiently manufactured?In order to consider these questions, several important elements of data-base requirements are regarded as essential. These include knowledge of the crystalline phases of pharmaceutical solids, full understanding of the fundamental mechanical constants and moduli of particulate solids, and the relationships describing the influence of crystallographic structure on the mechanical properties of crystals and powders. At the same time the effects of preparation, pretreatment and processing effects on crystal structure, crystallinity and thermodynamic properties of powdered solids must be established.The topics of material based compaction problems, property groupings of pharmaceutical powders with particular emphasis on crystal structure and mechanical properties are discussed. The review then considers recent and current research work examining the compaction behaviour of modified or engineered materials, prepared using alternative crystallisation conditions and the incorporation of low level additives. Specific examples include modern direct compression excipients, 'spherical' drug particle production and high purity lubricant (magnesium stearate) powders.In conclusion, the future potential of the concepts of crystal engineering and particle design is considered in terms of predicting mechanical and processing properties from fundamental molecular and structural information.