Multiparameter optimization problem

Process development is a multiparameter optimization problem. It is not surprising, therefore, that notv that the technology is available to parallelize and automate organic synthesis, it is applied in this field. 

We use MMP approaches to analyze primary SAR, selectivities, and anti-target S ARs. Results of an MMP analysis are presented in the form of HTML or PDF reports, which show the constant region of the molecular series on the left-hand side followed by the variable region of each individual compound (cf Figure 13.6) sorted by the property of interest. Activity can be substituted by any other property that is part of the multiparameter optimization problem, for example, solubility or ADMET endpoints. Data interpretation is facilitated by color coding. 

The Tophss Tree is an enduring tool for the iterative optimization of a chemical series where it is not possible to synthesize aU close analogs (i.e., for all medicinal chemistry projects) Figure 8.2 illustrates the practical application of the method. The continued popularity of the Tophss Tree (although, in the authors view, the tool is shU underused by medicinal chemists) is perhaps explained by the simplicity and visual applicatiou of the approach. However, the method is without a strong mathematical framework, which limits its apphcabihty to more complex problems, such as multiparameter optimization (MPO). 

A very interesting task would be automatic measurement of the product and the calculation of production rates. This would allow automatic optimization of the process by a computer program that varies all relevant parameters, probably by multiparameter analysis, to find the best production conditions. As long as there are no product sensors available, the main problem may be the time necessary for the measurement of an automatically taken sample. However, the use of HPLC methods can give accurate results within 20 min, and high-performance capillary electrophoresis (HPCE), with an analysis time of 5 min, could be introduced (Beckman PIACE 2(X)0, E. Wasserbauer, personal communication and James et al, 1994). Nonetheless, further development is necessary before these methods can be used routinely for automatic fermentation analysis. 

The critical components in PEMFCs are the CLs, where the electrochemical reactions take place that transform oxygen molecules into water at the cathode and hydrogen molecules into protons at the anode. Optimization of the CLs is a multiparameter problem, since they must meet numerous requirements simultaneously, ensuring optimum rates of electrocatalytic reactions as well as providing pathways for electrons, protons, reagents, and products. The strongest constraints are imposed on the cathode, where water molecules produced electrochemically must be transferred to the gas phase and removed from the catalytic layer to avoid its flooding. The latter leads to a drastic decrease in cell performance. 

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