Rapid Affinity and Microsomal Stability Ranking of Crude Mixture Libraries of Histone Deacetylase Inhibitors

The science of drug discovery involves multiparameter optimization of molecular structures through iterative design–make–test cycles. For medicinal chemistry library synthesis, traditional workflows involve the isolation of each individual compound, gravimetric quantitation, and preparation of a standard concentration solution for biological assays. In this work, we explore ways to expedite this process by testing unpurified library mixtures using a combination of mass spectrometry-based assays for affinity selection and microsomal metabolic stability. Utilizing this approach, microgram quantities of crude library mixtures can be used to identify high affinity, metabolically stable library members for isolation and full characterization. This streamlined approach was demonstrated for the synthesis and evaluation of two libraries of histone deacetylase inhibitors and was shown to generate decision-making data in line with traditional workflows. The advantages of this paradigm include greatly reduced cycle time, reduced material requirements, and concentration of resources on the most promising compounds.