Compound libraries for drug discovery
Axxam’s compound libraries accelerate high-throughput screening (HTS) and enable efficient hit identification across diverse discovery programs.
Our collections include more than 450,000 small molecules and combine universal libraries that offer broad chemical diversity with focused libraries tailored to specific target classes. In addition, our highly annotated virtual library further expands accessible chemical space and increases the chances of identifying relevant hits.
All collections are curated by experienced medicinal chemists who apply strict quality filters; therefore, reactive groups, frequent hitters, aggregators, toxicophores, and other undesirable moieties are systematically removed.
As a result, only high-quality, screening-ready compounds enter your discovery campaigns.
Why high-quality screening compound libraries matter?
High-quality screening compound libraries directly determine the reliability of hit identification, downstream development costs, and project timelines. Using poorly curated collections increases false positives and follow-up waste. Axxam’s libraries are designed to minimize these risks and accelerate confident decision-making in early drug discovery.
Our screening compound libraries
You can access universal, focused, and virtual libraries depending on your screening strategy.
Universal compound collections: AXXDiversity and Symegold
Axxam offers two complementary, high-quality compound collections — AXXDiversity and Symegold — curated specifically for screening applications in modern drug discovery.
These libraries are non-overlapping, flexible, and optimized to deliver maximum impact across high-throughput and high-content screening campaigns.
The AXXDiversity library is designed and continuously refined by Axxam’s medicinal and computational chemistry experts, while the Symegold library is made available through our strategic alliance with Symeres, who developed this unique lead-like collection.
Together, they enable fast, reliable, and diverse hit discovery across a wide range of biological targets.
AXXDiversity library
The AXXDiversity library contains ~350,000 carefully selected small molecules.
The collection is built on Axxam’s extensive screening experience and is continuously enriched based on chemical diversity, quality, and emerging scientific needs. AXXDiversity is available as part of screening campaigns performed at Axxam or as screening-ready plates (384- or 1536-well format) for in-house use.
The full collection is divided into five independent, non-overlapping sets, which can be accessed separately or combined according to project requirements.
- Around 180.000 molecules
- Mean of 15 analogues per chemotype
- Provides structure–activity relationship (SAR) information
- Approximately 98.000 molecules
- High coverage of structural diversity (enriched unique scaffolds)
- Ideal for novel peripheral and central targets
- Around 24.000 molecules
- High chemical tractability, for a fast hit expansion
- sp3-rich non-flat screening compounds with high chemical diversity
New expansion: ExplorerFASTER set
- Around 1.000 proprietary triazole-enriched compounds
- High chemical tractability for an accelerated hit expansion (one step synthesis)
- 95% of powders already available at Axxam
- Around 35.000 singletons
- Optimized MPO for a higher probability of blood-brain barrier and cellular permeability
- Specifically biased towards CNS, pain and intracellular targets
- Approximately 12.000 decorated fragment-like compounds
- Low molecular weight
- For an easy exploration of ligand-target interactions
Symegold
The Symegold library is available for screening at Axxam through our strategic alliance with Symeres, a leading contract research organization with deep expertise in medicinal, synthetic, and development chemistry, as well as ADME-Tox services.
The collection comprises approximately 78,000 lead-like compounds synthesized at Symeres as part of the European Lead Factory (ELF) IMI-2 consortium, using state-of-the-art parallel synthesis and purification technologies. Symegold provides access to structurally novel, lead-like chemical space that is not available in commercial libraries.
Its design is based on stringent criteria for lead-like properties and structural innovation, incorporating Symeres’ proprietary, rigid, sp³-rich scaffolds produced in-house through innovative synthetic chemistry.
Axxam focused libraries
Axxam’s focused compound libraries are specifically curated to explore defined biological targets, interaction mechanisms, and distinct chemical spaces.
These collections are designed to improve screening efficiency and strengthen hit discovery outcomes across challenging projects.
The portfolio includes:
- NatPure, one of the largest natural product libraries worldwide
- AXXRNABind, tailored for RNA-binding and RNA–protein interaction studies
- AXXCovalent, a covalent-focused collection targeting reactive amino acids
- AXXPPI, a machine-learning–derived library optimized for protein–protein interactions
- Symecycle, a unique macrocycle collection developed by Symeres
Each library provides a complementary entry point into novel chemical space and supports diverse screening strategies.
NatPure library
NatPure is one of the world’s largest pure natural product libraries, offering broad chemical diversity for drug discovery screening.
The collection contains ~15,000 natural products from plant and microbial sources, with ~30% being novel and unpublished. This diversity provides access to a unique chemical space represented by nearly 4,900 clusters, making NatPure a powerful resource for high-quality hit identification.
Key features:
- Proprietary compound collection
- Solids available for all the compounds
- Comprehensive analytical characterization
AXXRNAbind
AXXRNABind is a small molecule compound collection specifically designed to bind RNA. This collection is suitable to initiate discovery programs aimed at finding RNA splicing modulators and RNA-protein interaction modulators.
Key features:
- Around 2.000 drug-like and lead-like compounds
- High novelty and chemical diversity
- Optimal starting point for MedChem programs
AXXCovalent
AXXCovalent library includes ~9,000 compounds designed to support both covalent and non-covalent interactions. In addition, the collection meets strict quality and diversity criteria, as all compounds were synthesized within the last five years and maintain purity levels above 90%.
Key features:
- More than 50 different warheads
- High structural seeker diversity for target selectivity
- 62% biast towards Cys, Ser, and His residues, the remaining 38% employs a non-specific targeting approach Synthesized in the last 5 years
AXXPPI
Our Protein-Protein Interaction (PPI) small collection is specifically curated to facilitate the exploration of critical biological pathways. This diverse set of compounds is designed at Axxam using generative Machine Learning algorithms trained with PPI physico-chemical properties and retailored to ensure positioning within a more drug-like chemical space. It offers a valuable resource for researchers aiming to understand and manipulate PPI networks in drug discovery.
Key features:
- ~ 3.000 proprietary compounds, expected to reach 6.000 in 2026
- Specifically biased for Protein-Protein Interactions
- Solids available for all the compounds
Symecycle
Symecycle is a subset of ~1,900 proprietary macrocycles designed and synthesized at Symeres. In addition, the collection offers high novelty and balanced drug-like properties, with molecular weights ranging from 370 to 640 Da and cLogP values between –2.5 and 5.2. Since these compounds are not commercially available, they provide unique chemical space and enable rapid hit expansion using building blocks and reagents accessible at Symeres.
Key features:
- ~1.900 proprietary macrocycles
- Accessible as part of the Symegold collection or as a separate subset
- Good balance between complexity and druglikeness
- Building blocks and reagents available at Symeres for rapid expansion of hits
Axxam virtual library NEW
The AXXVirtual library is a meticulously curated collection of 19 million highly annotated non-commercially available compounds that meet physico-chemical and universal drug-likeness criteria. They have been designed to be quickly synthesized using reliable and well-established chemical reactions and starting from easily accessible building blocks. This enables a rapid exploration of the hits’ chemical neighborhood, optimizing and accelerating the research process. . Customizable screening sets can be easily selected to suit specific project needs.
