Maintaining a High-Quality Screening Collection: The GSK Experience.

The storage of screening collections in DMSO is commonplace in the pharmaceutical industry. To ensure a high-quality screening collection, and hence effective and efficient high-throughput screening, all compounds entering the GlaxoSmithKline (GSK) screening collection undergo a liquid chromatography-mass spectrometry (LC-MS) quality control (QC). It is generally accepted that even under optimal conditions, a small percentage of these compounds are unstable after prolonged storage in DMSO. This article presents how these QC data can be mined using a data-driven clustering algorithm to identify chemical substructures likely to cause degradation in DMSO. This knowledge provides new structural filters for use in excluding compounds with these undesirable substructures from the collection. This information also suggests an efficient, targeted approach to compound collection clean-up initiatives. Stability studies are also designed to maintain a high-quality screening collection. To define the best practice for the storage and handling of solution samples, GSK has undertaken stability experiments for two decades, initially to support the implementation of new automated liquid stores and, subsequently, to enhance storage and use of compounds in solution through an understanding of compound degradation under storage and assay conditions.

Method Development and Application of an Accelerated Solution Stability Screen for Drug Discovery.

An important aspect to understand about an experimental molecule in drug discovery is its stability in solution. A compound that degrades might be eliciting its apparent effect via a degradation product, so it is important to understand the solution stability profile of a compound early on in the drug discovery process. Improvements and application of a streamlined, higher-throughput method for testing solution stability to support drug discovery are described. Mass spectrometry detection has been incorporated into the screen to allow for the identification of degradation products. The amount of compound needed for the assay has been significantly reduced using 10 mM DMSO solutions instead of solid material. The buffers used in the screen provide the stability-pH profile of compounds with additional variations to assess liabilities under oxidizing and reducing conditions. In this article, we discuss the method development, screen validation, guidelines for result interpretation, and results for a set of marketed drugs to illustrate the application of the screen.