Where to get small molecule libraries

check-out: https://ncats.nih.gov/research/research-activities/compound-management/chemical-libraries

Europe

The most prominent example is EU-OPENSCREEN. It is a European Research Infrastructure Consortium (ERIC) that provides open access to a common compound collection and state-of-the-art high-throughput screening and medicinal chemistry facilities.

Key features of EU-OPENSCREEN include:

• The European Chemical Biology Library (ECBL): This is the core compound collection, which consists of over 100,000 carefully curated compounds with diverse chemical structures. This library is designed to explore new areas of biology and is continuously expanded with novel compounds from academic chemists across Europe.
• Access to Partner Sites: Academic researchers can submit a research proposal, and if accepted, they can access the ECBL and screening services at one of the many affiliated screening centers located in various EU countries (e.g., Germany, Spain, Finland, Poland).
• Services: Beyond just providing compounds, EU-OPENSCREEN offers expertise and resources for every stage of a chemical biology project, from assay development to high-throughput screening and hit optimization.

Another important initiative was the European Lead Factory (ELF), a public-private partnership that created a large compound library and a high-throughput screening center. While the initial project has concluded, it established a massive Joint European Compound Library of over 500,000 compounds, which included contributions from major pharmaceutical companies and newly synthesized compounds from academic and SME partners. The resources and expertise developed by ELF are now being continued through subsequent projects and collaborations, and its compound collection remains a significant asset in European drug discovery.

To obtain access, a university research group would typically need to:

1. Develop a screening assay: The research group must have a robust, validated assay for their specific parasite target (e.g., an enzyme or a cellular process).
2. Submit a proposal: The group must submit a project proposal to the relevant screening infrastructure (e.g., via the EU-OPENSCREEN website).
3. Collaborate: If the proposal is accepted, the project proceeds in collaboration with the screening center's experts, who will perform the high-throughput screening and provide support for hit validation.

Academic Collaborations and Public Repositories

This is often the most cost-effective and collaborative approach for university groups. Many academic institutions and government-funded initiatives have established compound repositories specifically for research purposes.

• NIH Molecular Libraries Program: The National Institutes of Health (NIH) has funded the creation of large, diverse small molecule collections, such as the Molecular Libraries Small Molecule Repository (MLSMR). These libraries are often made available to academic researchers through screening centers. Researchers can submit their assays for high-throughput screening against these large collections.
• University Screening Centers: Many universities have their own high-throughput screening centers and compound libraries, which they make available for internal and external collaborations. Examples include the Yale Center for Molecular Discovery and the University of Michigan's Center for Chemical Genomics. These centers provide expertise and access to a wide variety of libraries, including those focused on specific compound types like natural products or FDA-approved drugs.
• Open-Access Initiatives: Projects like the ChEMBL-NTD (Neglected Tropical Diseases) database provide a repository of open-access data, including screening results and chemical structures, which can be useful for in silico(computational) screening. While this doesn't provide a physical library, it can help narrow down a list of promising compounds to acquire from other sources.

Commercial Vendors

• Diversity Libraries: Companies like ChemBridge, Enamine, and Maybridge (Thermo Fisher Scientific) offer large, diverse libraries designed to cover a broad range of chemical space. These libraries are ideal for primary, or "hit-finding," screens. They are pre-filtered to exclude problematic compounds and are often available in "drug-like" or "lead-like" sets.
• Targeted/Focused Libraries: Vendors also sell smaller, more specialized libraries. These include libraries of FDA-approved drugs (e.g., from SelleckChem or Prestwick), natural products, or compounds targeting specific protein families (e.g., kinases, GPCRs). These are excellent for drug repurposing projects or for screening against targets where some prior knowledge exists.