4.2.1. Thermal Gravimetric Analysis (TGA)

TGA is one of the oldest thermal analytical procedures and has been used extensively in the study of material science. The technique monitors changes in sample weight, usually nitrogen, as a function of temperature. TGA can be used to facilitate the assessment of processing temperatures of thermally based secondary manufacturing processes such as hot-melt extrusion while also finding utility in determining the presence of residual solvents or moisture. When used as a pre-formulation tool for hot-melt extrusion, TGA is used to determine the thermal stability of the polymers and nanocrystalline API. It allows for the determination of a range of operating temperatures in hot-melt extrusion. This is done in order to avert thermal degradation that may occur during the manufacturing process. TGA can also be used to determine the moisture or residual solvent contents as well as the presence of a solvate in NCM, especially in the instances where a crystallization step was part of the synthetic process of a given NCM.
