1.2 History

When filter began in 2000, it was designed simply to remove compounds with reactive or otherwise undesirable functional groups. Over the years, the understanding of lead-like and drug-like compound selection has advanced. In addition, with the publication of Lipinski's ``Rule of 5'' [1], more and more pharmacokinetic properties have been pushed earlier into the virtual screening process.

In its current version, Filter still provides the basic functional group selection, but it now also has many additional database preparation features. It allows selection based upon several physical properties (MW, LogP, LogS, PSA), assay counter-indicators (aggregators and dyes), PK (ABS, Veber, Egan, Lipinski). It allows database preparation in the form of setting pKa states, normalizations (tautomers & dative or hypervalent states). Finally, it provides excellent cheminformatics quality-control in the form of valence-state validation, aromaticity perception, implicit hydrogen perception and bond-order perception. Filter is a one-stop database preparation tool aimed at generating databases suitable for high-throughput virtual screening.

Finally, we want to point out that in the virtual screening world, time is of the essence. Algorithms for preliminary database preparation should not take extremely large amounts of time. Because of this, we have taken that philosophy that all the calculations included in Filter should be 2D or graph-based algorithms. While this does occasionally limit the technology we are willing to include in Filter, we feel it allows us to deliver a product that is appropriate for the task of virtual-screening database preparation.

				FILTER Database preparation Property calculation

				FILTER Database preparation Property calculation