Comparability testing physicochemical characterization

The availability of sensitive analytical tests to adequately characterize a product and to measure the predicted possible changes is central to a comparability assessment. Obviously tests should be chosen that will be the most likely to detect important changes. ICH Q6B offers advice on physicochemical, biological activity, and immunochemical properties, purity (impurity), con-... 

The ammonium salt of Rh(III) Anderson type heteropolymolybdate [RhMo6024H6] has been prepared and characterized by powder X-ray diffraction, spectroscopic [FTIR-Raman, DRS (UV-visible)] and SEM-EDAX electron microscopy techniques. The water soluble salts were used in the design and preparation of Y-AI2O3 supported catalysts. The varied Mo Rh ratio of both olution and solid samples was measured by AAS technique. The supported oxidic system was characterized by DRS spectroscopy and SEM-EDAX microscopy. The HDS and HYD activity for different bimetallic catalysts was measured in a high-pressure reactor. In addition, some conventional catalysts and some C0M06 and combined supported systems [(RhMoe + AIM06)] have been tested for comparative purposes. The discussion about the performance of the new catalysts is made on the basis of the structural and physicochemical heteropolyanion properties as well as the preparation conditions. 

A standard practice is to characterize SAS by physicochemical data [1]. Some difficulties are encountered when the data given by different manufacturers are compared first, because test methods have not been generally adopted [dibutyl phthalate (DBF) adsorption, pore distribution, and methanol wettability], and second, because the correlations with the application-related properties, which are of interest to the user, are not widely known. 

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