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Browsing by Subject "virtauskammio"

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  • Svanbäck, Sami (2013)
    The dissolution rate is one of the most important physicochemical properties of drug substances. Above all, it demonstrates the energetic interaction between solvent and solute molecules, and is therefore a valuable tool for understanding drug substance properties. Dissolution studies are a widely used method in many areas of the pharmaceutical development process, however, only lately has the value of dissolution testing in drug discovery and early development been assessed. The advantages of dissolution testing over other early screening methods, such as kinetic solubility and in silico screening, lies in the possibility of obtaining solid state dependent quantitative data, from small amounts of drug substances. While the general way of studying drug dissolution has been by the multiparticulate bulk approach, studying the constituent single particles of these systems, could give a deeper understanding of the core factors affecting the dissolution rate of drug substances. The aim of the present study was to develop a static and dynamic method, in which it would be possible to analyze the dissolution process of a single pure drug substance particle, by optical microscopy. Both methods produced practically identical dissolution profiles, for image analysis and UV-spectrophotometric data, from the same systems of a single dissolving particle. The dynamic method developed in the present study is the first flow-through technique, in which it is possible to assess the dissolution of a single freely moving drug particle, by continuous physical analysis. The possibility of using physical analysis instead of chemical analysis poses many advantages. These include reduced materials consumption, reduced experiment times, as well as a reduction in the possible sources of error. Most importantly, the advantage of physical analysis lies in the fact that no prior chemical knowledge about the studied substance is needed. This makes physical analysis an optimal technique for studying new chemical entities. The novel flow-through method succeeded in obtaining the dissolution characteristics and 3D particle morphological data, of a single pure drug substance particle, of sub-milligram initial weight. The theoretical detection limit of 1 pg, poses an intriguing opportunity for further development.