Methods for screening compound libraries

Abstract

Disclosed are methods for screening compound libraries using frontal chromatography in combination with mass spectrometry to identify and rank those members of the library that bind to a target receptor. Methods are also disclosed which permit a compound library to be rapidly screened to determine if any member of the library has an affinity for the target receptor as measured by a pre-selected indicator compound.

Description

[0001] This application is a continuation-in-part of U.S. Ser. No. ______, filed Dec. 28, 1998 (Attorney Docket No. 026579-248); which application is a continuation of U.S. Ser. No. 09 / 070,131, filed Apr. 29, 1998, now abandoned; which application claims the benefit of U.S. Provisional Application No. 60 / 079,622, filed Mar. 27, 1998. Each of these applications are incorporated herein by reference in their entirety.[0002] 1. Field of the Invention[0003] This invention relates to methods for screening compound libraries, such as compound libraries generated using combinatorial chemistry techniques. The methods of this invention employ frontal chromatography in combination with mass spectrometry to screen a library of compounds to identify and rank those members of the library that bind to a target receptor. The methods of this invention also permit a compound library to be rapidly screened to determine if one or more members of the library have an affinity for a target receptor as mea...

AI Technical Summary

Benefits of technology

[0158] A particular advantage of the present method is that compound libraries containing isomers may be screened to determine, for example, if only one isomer (e.g. an enantiomer or diastereomer) is binding to the target receptor, or if the isomers have different affinities for the target receptor. In this regard, if the isomers have different affinities for the target receptor, a different break through time will be observed for each isomer.

[0193] Alternatively, the indicator compound and the void marker compound, without the compound library, can be applied or infused into the column after equilibration or partial equilibration of the column with the compound library. This technique allows very strongly bound ligands or those with slow off rates to be detected.

Problems solved by technology

The traditional approach of screening each compound individually in an assay to identify those compounds having the desired biological activity is no longer practical due to time and resource constraints.

While such methods can be effective, the need to keep track of individual members of the library during their synthesis and screening is quite cumbersome and often limits the type of synthetic procedures that can be employed.

Additionally, many of these techniques require that the synthetic procedures be conducted on a solid phase, thus further limiting the synthetic procedures and reagents that can be used.

There are several disadvantages associated with the "capture and release" methods for screening compound libraries that have been previously reported.

First, the procedure used to "release" the bound ligands from the ligand-receptor complexes may alter the binding profile for the various bound ligands, resulting in a false indication of binding strength.

For example, using a pH gradient to release the bound members of the library may change the electronic character of the binding site on the receptor causing ligands which are strongly bound under physiological conditions to be prematurely released.

Thus, the characterization of binding strength for various ligands based on their relative time of release may be misleading if the release conditions are different from the binding conditions.

Accordingly, these methods may not accurately identify the most active members of a compound library.

Additionally, certain conditions used for compound release, such as pH gradients, may irreversibly denature the receptor thus preventing its subsequent use for screening compound libraries.

Additionally, when "capture and release" methods are employed, each bound ligand is typically released over a relatively short period of time resulting, for example, in an elution peak or "spike" for each ligand.

Thus, the number of analyses that can be conducted using any particular mass spectrometer is limited.

Images