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[FreeDry]

This is just a short post meant as an overview of analytical methods for freeze dried samples.
Apart from DSC, there are other possibilities to characterize a product:

Karl-Fischer-titration is a method to determine residual moisture content. It can be performed by either dissolving the sample in a water-free solvent (usually dry methanol) and inserting this solution into the titration cell or by heating the sample and vaporizing any sorbed water. The water vapor is then carried by an inert gas flow into the titration cell.

SEM, Scanning Electron Microscopy allows to take pictures of the micro structure of a sample. If you want to check a product for traces of collapse, this is the mehtod of choice.

XRD, X-Ray Diffraction: a method to determine whether or not a given product crystallizes during lyophilization. Not only can you determine which substance in the mixture has crystallized, but also which crystal modifications have formed and if there are crystal hydrates.

[ramshanpharm]

Good categerization of techniques.

In to above mentioned techniques, for protein biologicals you can use FT-IR also. It is an excellent method to analyze the secondary structure perturbations before & after lyophilization.