Impurity components

Impurity component Raw NaNT /wt-% Purified NaNT /wt-% Impurity removed /wt-%... 

Figure 629 (a) UV trace of the drug, (b) mass chromatogram of mJz 486 of an impurity component and (c) two-dimensional contour plot of the mass spectra from mIz 400 to mIz 550. Reproduced from [22] with permission of John Wiley and Sons Ltd. 

The product presents unreasonable health risks to the subjects in the initial IND trials (C. F., a product made with unknown or impure components). 

It is most unusual for only a single desired reaction to occur in a chemical reactor. Nature is typically not that generous and exacts a penalty that takes the form of side reactions generating undesired impurity components. The side reactions can involve other transformations of the reactant species (in parallel with the desired reaction) or further... 

CMC information It should contain sufficient detail to assure identification, quality, purity, and strength of the investigational drug. It should include stability data of duration appropriate to the length of the proposed study. FDA concerns to be addressed focus on products made with unknown or impure components, products with chemical structures known to be of likely high toxicity, products known to be chemically unstable, and products with an impurity profile indicative of a health hazard or insufficiently defined to assess potential health hazard, or poorly characterized master or working cell bank. 

Reasons for concern may include (a) a product made with unknown or impure components, (b) a product possessing chemical structures of known or highly likely toxicity, (c) a product that cannot remain chemically stable throughout the testing program proposed, (d) a product with an impurity profile indicative of a potential health hazard or an impurity profile insufficiently defined to assess a potential health hazard, or (e) a poorly characterized master or working cell bank. 

Whisker growth of hexagonal /3-HfP, cubic o -ZrP, and hexagonal jS-TiP is possible via a nuxed-metal, impurity-activated chenucal vapor deposition (CVD) process from HfCLi/ZrCLi/TiCLi + PCI3 -L H2 -E Ar gas mixtures at 1050 °C. Si-EPd and Si-EPt were used as nuxed-metal impurity components. Such whiskers are stable in concentrated HCl. ... 

The use of directed chemical reactions opens up a number of new opportunities in trace impurity analysis, such as the determination of compounds whose peaks are overlapped completely or partly by the zone of the main component or elimination of the superposition of the peaks of impurity components in their incomplete separation. Table 5.8 shows the application of the subtraction method to impurity analysis. 

For a simple system in which a solid solution is not formed and an ideal solution in the melt is formed, the mole fraction of solute impurity, component 2) in the solvent [component 1K is given by... 

In both, layer and suspension crystallization solid material forms from the melt starting with a nucleus through which a solid/liquid interface is created. As crystallization proceeds the mass of solidified substance steadily increases which causes the interface to move. The impurity components remaining in the melt thereby enrich in front of the solid/liquid interface, forming a concentration boundary layer. The concentration profile in this boundary layer changes as the interface advances which is in literature referred to as moving boundary problem. ... 

Figure 11. Variation in relative activity for a cobalt/rhenium/ alumina catalyst by adding traces of an impurity component.

Although we say we can separate mixtures into pure substances, it is virtually impossible to separate mixtures into totally pure substances. No matter how hard we try, some impurities (components of the original mixture) remain in each of the "pure substances."... 

In Figure 8.2-9 the phase diagram for an eutectic solidifying binary nrixture is shown. According to the given phase diagram (binary system without formation of mixed crystals) this soUd should contain less A than the feed. In this case the thermodynamic distribution coefficient for an impurity component i is defined by... 

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