Compression analysis as a tool for technical characterization and classification of pharmaceutical powders
Abstract: 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.
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