Design methods concept

GR Marshall, CD Barry, HE Bosshard, RA Dammkoehler, DA Dunn. The conformational parameter m drug design The active analog approach. ACS Symp Ser 112 205-226, 1979. YC Martin. Overview of concepts and methods in computer-assisted rational drug design. Methods Enzymol 203 587-613, 1991. 

Length of Unused Bed. The constant pattern approximation provides the basis for a very useful and widely used design method based on the concept of the length of unused bed (LUB). In the design of a typical adsorption process the basic problem is to estimate the size of the absorber bed needed to remove a certain quantity of the adsorbable species from the feed stream, subject to a specified limit ((/) on the effluent concentration. The length of unused bed, which measures the capacity of the adsoibei which is lost as a result of the spread of the concentration profile, is defined by... 

As with many drying calculations, the most reliable design method is to perform experimental tests and to scale up. By measuring performance on a single tray with similar layer depth, air velocity, and temperature, the SDR (specific drying rate) concept can be applied to give the total area and number of trays required for the full-scale dryer. 

If an active compound is detected by biological tests, then several of its derivates are prepared, in order to choose the one which shows the best biological characteristics. In this phase of research an opportunity offers itself even on the basis of our present knowledge to rate theoretical concepts into consideration. When a certain number of derivatives has been prepared, the computerised mathematical processing of data about them can reveal quantitative structure-activity relationships, on the basis of which the efficiency of compounds not yet prepared can be predicted with a high probability, and the compound which promises to be the most efficient can be selected. The rapid development of these mathematical molecule-design methods and the consequent increased success rate make it possible to work out the structure of effective compounds, and considerably fewer compounds have to be prepared than formerly. 

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