Many pharmaceutical solids exhibit polymorphism, i.e., the ability of a substance to exist in different crystalline forms. The polymorphic form can have significant influence on pharmaceutical processing and can, for example, affect grinding, granulation and tabletability. A DSC measurement allows for the characterization of the present modification. Here, different modifications of paracetamol are distinguished by means of DSC.
Caffeine exists under 2 polymorphic forms (I and II). Compression of form I induces its transformation into form II, leading to changes in its properties. Heating with DSC ensures that caffeine is in the correct form.
Spray-dried a-lactose monohydrate is a matrix of amorphous lactose in which lactose monohydrate crystals are embedded. Humidity has no influence on the crystal but amorphous lactose is very hygroscopic: in presence of humidity, it will transform into the crystalline form. This has consequences on the tableting properties of the substance. Thermal Analysis gives you first Information about the water content of your lactose and the consequences for its compressing properties.
The glass transition of lactose is in direct relation with the stickiness and the flowability of powders containing it. This in turn influences the processing.
How to determine the shelf life of drugs without long time testing? First predictions about the shelf-life concerning thermal stability are achieved using thermogravimetric measurements with a kinetics Evaluation. This occurs within some hours or days.
Each of the modifications of a polymorph has different physical properties. That´s why they have to be characterized before processing, for example using DSC.
The database system for thermal analysis by NETZSCH, called Identify, has now (from Proteus® analysis version 8.0 or higher) already more than 2000 database entries available.
Furthermore, Identify can now be used with combined TGA+DSC, TGA-c-DTA® and STA measurements, which allows for material identification with greater certainty.
AutoEvaluation by NETZSCH is a very helpful tool for evaluation of thermoanalytical measurements. The entire measurement is evaluated by AutoEvaluation automatically and autonomously (not via pre-defined macro!) – with only one mouse click – and just within a second. AutoEvaluation is available for DSC, TGA and now also for STA measurements. Furthermore, the adaptability of AutoEvaluation is adressed.
Thermal stability of materials measured fast and easy with a thermobalance coupled to a FT-IR System. Here, this method is applied to determine the thermal stability of Eudragit® L100-55.