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  • Author or Editor: U. Hess x
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Abstract  

The reaction calorimeter CAP202 (chemical process analyzer) determines thermal effects by measuring the true heat flow (THF) based on unique design principles. In particular, measurements can be performed without requiring any calibration procedures and the obtained results are most reliable and exhibit extremely stable baselines. The benefits in respect of experimental speed, data quality and long term performance are obvious. Due its broad dynamic range the instrument can be employed for measurements ranging from small physical heat to energetic chemical reactions. The CPA allows running experiments seamlessly with reaction volumes between 10 and 180 mL. This volume flexibility simplifies the investigation of multi-step operations and is the basis for various applications employing precious or highly energetic compounds. Due to the fact that calibrations are not required, altering conditions during a single experiment like changes in viscosities, liquid levels or stirring speeds do not affect the results of the measurements.

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Abstract  

The interaction among moisture content, solvent loss and glass transition temperature is relevant for processing of spray-dried pharmaceuticals, since the glass transition temperature determines the application range of a compound. Conventional Differential Scanning Calorimetry (DSC) does usually not allow to separate glass transitions from common kinetic effects like evaporation or crystallization. Based on classical DSC methods, the IsoStepTM method allows the independent determination of heat capacities and kinetic effects, and thus, the separation of kinetic effects from effects arising from heat capacity changes. This technique is used to separate glass transition and evaporation processes, and to find the relation between moisture content and glass transition temperature for a pharmaceutical sample based on a modified Gordon–Taylor equation.

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