Shelf-life studies of drug substances in commercial dosage forms are an essential element of the QC process for manufactured pharmaceuticals. While there are well described test procedures available, getting a quick insight to possible shelf-life issues is valuable—and important. Rapid wet and dry or low and high temperature cycling provides a strong indication of potential issues.
Such test procedures can be carried out easily using an environmental scanning electron microscope (ESEM) in which temperature and humidity can be precisely controlled and dissolution processes are observable in real time, which provides an extraordinary level of insight into the process.
Combining the ESEM with an Energy Dispersive Spectroscopy (EDS) detector also enables mapping the different elements in a formulated product to study the homogeneity of the product and the composition of all layers. Even more advanced studies can be carried out using an ion beam combined with a SEM in a small DualBeam microscope. The ion beam acts as a micro-scalpel, enabling investigation of a dosage form, such as a tablet, in all three dimensions. In this way the integrity of the tablet coating, for instance, can be investigated under the different environmental conditions required for shelf life testing.
FEI's Quanta 3D model provides great productivity for drug product characterization and pharmaceutical QC. The proprietary vacuum system of this microscope even allows high temperature experiments for phase transitions studies, as well as hydration and dehydration experiments to qualify the crystal behavior.