Amorphous content determination by Solution Calorimetry: A Quality Perspective

Mridul Majumder

M2M Pharmaceuticals Ltd, Science & Technology Centre, University of Reading, Reading RG6 6BZ, UK

Summary

Solution Calorimetry is a semi-adiabatic technique for high precision measurements of the heat generated or consumed when a solid or liquid sample is dissolved or diluted into a solvent. The instrument is designed for highest accuracy, precision and is used in general thermodynamic investigations as well as for quantitative analytical measurements of various solid-state phases. In this study, crystalline sucrose is used as a standard and amorphous form is made by quench cooling. As expected, the heat of solution for crystalline and amorphous forms are endothermic and exothermic respectively. To the best of our knowledge, there has been no reported heat of solution measurement for quench cooled amorphous sample until now. However, the results and quality of the sample suggested that quench cooled amorphous sample could be used as a calibrant to calibrate solution calorimetry whereby a real-time data for two opposite reactions could be achieved. A linear calibration plot is attained and the difference between a calculation based on calibration equation and an EP method remain within an acceptable limit. As the demand and requirements are ever increasing from a quality and data integrity perspective this work demonstrates how to use this technique to reproduce consistent data with a robust process. The study demonstrated that given a right skills, knowledge and experience, consistently reproducible data can be obtained using this technique.