Numbers and Costs

When compound libraries were small and contained mainly islands of traditional medicinal chemistry research (compound collections), the size of these collections was in the low hundreds of thousands. Today, well-run company libraries will contain several millions of compounds from in-house efforts, supplemented by external acquisitions from third parties and vendors. Building libraries of this size does cost money but is an investtnent. A properly maintained library will last for years, due largely to the continuing trend toward better automation technologies and more sensitive assays. 

Reluming to the origin of the compounds in the library and the in-house/third-party sources, the approximate comprative costs associated with preparing sufficient material to perform assays and retain archive amounts are  

The handcrafted compounds from third parties are generally compounds that have been collected by vendors from academic sources which meet the selection criteria set by pharmaceutical companies for their compound acquisition programs. It is not our purpose to make a case for or against any particular source of compounds in the library it is to arrive at an approximate cost for a library of useful size. A nicely balanced library with 1 million compounds will cost between 25 million and 50 million to purchase. The costs of proper storage, retrieval, and maintenance are not included (see below). 

A controlled number of analogs does therefore seem wise. But how many, and with what structural variations A series of chain homologs would, without thinking about it too much, seem not a good way to go about selecting analogs for the library. What difference does a methylene group make in a hydrocrabon chain The answer is that it can make a 

Ten milligrams of a compound in the library is an acceptable amount to support years of HTS and even for special characterization in the event of a hit. But more of the compound will be required if the hit is to be developed into a lead and beyond. Even today, as the minimum amount required for HTS and characterization continues to fall, some companies prefer to play it safe and have as much as 100-mg amounts in the library where possible. 

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Selectivity. Solvent selectivity is intimately linked to the purity of the recovered extract, and obtaining a purer extract can reduce the number and cost of subsequent separation and purification operations. In aqueous extractions pH gives only limited control over selectivity greater control can be exercised using organic solvents. Use of mixed solvents, for example short-chain alcohols admixed with water to give a wide range of compositions, can be beneficial in this respect (6). 

It is possible to run two or more indoor units from a single condensing unit, with economies in the number and costs of components. Such systems are referred to as multisplits, and several different types of circuit will be encountered. 

Fire Protection Association. 1974. Increasing number and cost of fires in chemical process industries. Fire Prev., Vol. 106, p. 15. 

Cynthia is using a secondary data source to conduct her cost-benefit analysis. After she has identified her variables of interest, she asks the HMO to provide her with baseline information on all heart failure patients prior to implementing her service. The HMO is able to stratify the data by diagnosis, so Cynthiaasks for annual numbers and costs of hospitalizations, emergency room visits, and medications for their heart failure patients (see Table 27-3). 

GhI> (VA) To evaluate clinical RPh recommendations on number and costs of drugs OD Control group None DCA Decreased average monthly drug cost/patient Input costs not considered... 

Rovida C, Hartung T (2009) Re-evaluation of animal numbers and costs for in vivo tests to accomplish REACH legislation requirements for chemicals—a report by the transatlantic think tank for toxicology (t4). ALTEX 26 187-208... 

The flip side of this coin is that tests of efficacy and safety could continue to proliferate. The number of tests that regulators could wish to see performed may increase to provide better evidence of safety and efficacy. If more population subtyping leads to an increased demand for studies of more refined groups that could not be distinguished before, then costs could go up rather than down. Here again, scientific advance is a two-edged sword. Each experiment or trial can be more precise, but the number and cost of experiments may go up as well. It is difficult to predict which effect will be greater. 

In summary, the number and costs of workplace injuries, illnesses and fatalities are unacceptably high. Injury and illness prevention programs have been proven to help employers and society reduce the personal, financial and societal costs that injuries, illnesses and fatalities impose. As described below, the thousands of workplaces that have implemented these programs in some form have already witnessed the resulting benefits, in the form of higher efficiency, greater worker productivity and lower costs. 

Continued advances in the performance of various analytical techniques, as well as their increasing availability in terms of both number and cost, are expected to drive the number of operando and in situ studies upwards in the coming years and into the foreseeable future - an undoubted benefit in the quest to develop more efficient catalysts and catalytic processes. Such developments may also prove crucial for realizing more sustainable technologies in the near future. 

The resolution of fraction collection can be dynamically controlled to lower sample number and costs of measurement. Variable width fractions are possible... 

Table 5b Number and costs of academic collaborators of LG. Farben Number of contracted outside collaborators ...

Mulligan S. AARC and Gallup estimate numbers and costs of caring for chronic ventilator patients. AARC Times 1991 15 30-36. 

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