Triazolylidene NHCs decorated with a carbohydrate wingtip group were complexed to a ruthenium(ii) center. Deprotection of the carbohydrate in the metal complex affords a carbohydrate–NHC hybrid system for use as a transfer hydrogenation catalyst.
Abstract. Bulk density can be a key indicator of performance, and may influence choice of formulation route of materials in pharmaceutical development. During early development, the cost of API's can be expensive and the availability of material for powder property analysis is limited. The aim of this work was to investigate a suitable small-scale, low material requirement, bulk density test which would provide comparable data to the recommended large volume USP test. Materials with a range of morphological characteristics typically seen in the pharmaceutical industry were assessed to ensure that methods were suitably robust. It was found that the USP II "low volume" test does not give equivalent results to other tests in the USP, across the range of materials. An alternative test based on the FT4 powder rheometer at a scale of 25 mL gave results equivalent to the large volume USP I standard test. The use of smaller 10-mL methods was also found to give acceptable results for materials that were considered well-behaved but were more variable with difficult to handle materials with low bulk density.
The aim of this study was to determine the location of attrition of formulated API particles within a powder feed system using a Morphologi G3-ID system, an image analyzer with integrated Raman capability enabling classification of particles with respect to their chemistry, to extract the API size distribution from the blended sample. The study also aimed to investigate the impact of other process variables, such as feed screw speed, on the extent of attrition observed. The study demonstrated that attrition occurs in two zones of the powder feed system, at the bottom of the hopper at the interface with the feed screw, and also within the feed screw itself. In the situation of the attrition at the bottom of the hopper variations in the hopper fill level were not observed to change the extent of attrition observed. Variation of the feed screw speed was observed to affect the extent of API attrition, with the particle size within the formulation observed to decrease with increasing speed. The findings highlight that an understanding of the impact of unit processes, and variations in the associated processing conditions, is vital in order to fully understand the behavior and performance of pharmaceutical dosage forms.
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