Thermal Analysis with Pharmaceutical Applications
Karen Griffin, Senior Analytical Chemist
Thermal analysis techniques, such as differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to characterize the properties of a variety of materials, including polymers, ceramics, and pharmaceuticals. Test materials can be solids, semi-solids and liquids and the atmosphere can be nitrogen or air. The DSC provides a wide range of information on a test material by monitoring endothermic and/or exothermic events (e.g. glass transition (Tg), melting point (MP), decomposition) at either isothermal or dynamic temperature profile. The TGA is commonly used in conjunction with the DSC results. The TGA monitors weight of the test material over a temperature range or over time at a specific temperature. A sharp exothermic peak in a DSC thermogram may be attributed to crystallization or decomposition of the test material. For decomposition, the TGA thermogram would show a corresponding decrease in the weight of the test material over the equivalent. These techniques were used to study the effects of lyophilization on a test material, and as a measure of quality control, as will be discussed here.
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