Loss on Drying
This test determines the amount of volatile matter, of any kind, that can be driven off under specific conditions in powders. This is important for verifying the purity of the sample itself minus any volatile substance present, without degrading these sample as other methods of removing the moisture content can do. Loss on Drying (LoD) is a determination of any volatile substance in an API or formulated product, such as a capsule or tablet. Volatile substances would include residual solvents, as well as water. The technique can involve heating the test sample, vacuum drying, or desiccating and determining the % LoD by a change in its weight. If total water content is desired, Water Determination, via Karl-Fischer, is the more appropriate test.