Physiological relevance defined

So far, certain biomimetic catalysts (1 and 2b in Fig. 18.17) have been shown to reduce O2 to H2O under a slow electron flux at physiologically relevant conditions (pH 7,0.2-0.05 V potential vs. NHE) and retain their catalytic activity for >10" turnovers. Probably, only the increased stability of the turning-over catalyst is of relevance to the development of practical ORR catalysts for fuel cells. In addition, biomimetic catalysts of series 1,2,3, and 5, and catalyst 4b are the only metalloporphyrins studied in ORR catalysis with well-defined proximal and distal environments. For series 2, which is by far the most thoroughly studied series of biomimetic ORR catalysts, these well-defined environments result in an effective catalysis that seems to be the least sensitive among all metalloporphyrins to the electrode material (whether the catalyst is adsorbed or in the film) and to chemicals present in the electrolyte or in the O2 stream, including typical catalyst poisons (CO and CN ). 

Furthermore, in a recent study by Takei and colleagues, the ginsenoside metabolites Ml (Compound K) and M4 (20(S)-Protopanaxatriol) were demonstrated to promote the maturation of human monocyte-derived DCs [48], M4, and to a lesser extent Ml, increased the DC expression of key costimulatory molecules, decreased their endocytic activity, and induced their production of IL-12. Moreover, these effects had the end result of generating mature DCs that could induce potent Thl polarization. Unfortunately, it was not clearly defined in this study if the ginsenoside metabolites were used at physiologically relevant concentrations, a variable that would be expected to have significant implications on the interpretation of these results. 

An in vitro dissolution method for batch QC is always defined for a new solid dosage form product. However, this method may not be sufficient for all the different aims of dissolution testing that might arise. The choice of dissolution method and test conditions should therefore be adapted to best serve their purpose. For example, simplicity and robustness are crucial properties of a QC method whereas physiological relevance may overrule these factors when a method is used for in vivo predictions. 

Although the focus of this report is the analysis of physiologically relevant lipid mixtures, some comments on typical patterns of MALDI-TOF mass spectra of lipids will be given on the hand of defined lipids. 

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