Computer-aided disc

The second activity is characterized by the revitalization of older instrumental methods such as gravitational and centrifugal sedimentation methods. Redesign, modernization with advanced electronics, and user-friendly, computer-aided analysis have extended the instrument product life cycle. A good example is disc centrifuge photosedimentometry (DCP), the subject of three chapters in this volume. 

Only a few compounds screened in early lead identification phases are synthesized in-house. More flexible and cost effective is to purchase chemicals from external suppliers. Most vendors provide lists of some ten to himdred thousand chemicals on compact discs and guarantee delivery within days to weeks. To explore this huge amount of data with the aid of computers, chemical information is transformed to computer-readable strings, e.g., smiles code, and different descriptors are determined. 1-dimensional (1-D) descriptors encode chemical composition and physicochemical properties, e.g., molecular weight, stoichiometry (C O Hj,), hydrophobicity, etc. 2-D descriptors reflect chemical topology, e.g., connectivity indices, degree of branching, number of aromatic bonds, etc. 3-D descriptors consider 3-D shape, volume or surface area. 

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