ChemBridge has assembled an exemplary collection of small molecules useful for fragment-based screening: the Fragment Library. The emergence and development of high throughput X-ray crystallography and NMR methodologies for drug discovery have contributed widely to the acceptance and implementation of fragment-based screening. The ability to detect low affinity binders has proven invaluable in the introduction and promotion of this aspect of drug discovery and design. The Fragment Library was chosen based upon the commonly accepted Astex Rule of Three1 as well as proprietary ChemBridge substructure filters.

Fragment Library Selection

Compounds are selected according to various diversity parameters and Astex Rule of Three considerations (MW ≤ 300, H-bond donors ≤ 3, H-bond acceptors ≤ 3, cLogP ≤ 3). The commonly publicized cLogSw (calculated aqueous solubility) lower limit can be as low as -3.50, however, the -2.50 limit (approx. 3mM) applied by ChemBridge ensures a higher calculated aqueous solubility. Structural diversity of the fragment library has been independently assessed, confirming that the overall selection displays good diversity.