Box 2 | Rapid Elimination Of Swill

From the following article:

Designing screens: how to make your hits a hit

W. Patrick Walters & Mark Namchuk

Nature Reviews Drug Discovery 2, 259-266 (April 2003)

doi:10.1038/nrd1063

Rapid Elimination Of Swill (REOS) is a hybrid method that combines a set of functional group filters with some simple counting schemes similar to those in the rule-of-5. The initial filtering is based on a set of set property filters. The default values for these filters are shown in the Table. In addition to the property filters, REOS also employs a set of more than 200 rules based on the presence of chemical functionality known to be problematic. These rules have been developed over the past seven years and are the result of contributions by scientists throughout the Vertex organization. Rather than providing a simple 'accept/reject' facility, REOS allows the user to specify a maximum allowed quantity for each functional group rule. Importantly, rules can be custom tuned to suit the needs of specific targets or assay formats. Examples of the functional group filters employed by REOS are illustrated in the figure.

Designing screens: how to make your hits a hit