smallmoleculelike

Smallmoleculelike is a term used in drug discovery and medicinal chemistry to describe compounds that share characteristics with known small molecule drugs but may not be actual drugs themselves. It refers to molecules that possess a molecular weight, lipophilicity, and other physicochemical properties typically found in orally bioavailable drugs. The concept helps researchers identify promising lead compounds during the early stages of drug development.

These "smallmoleculelike" compounds are often synthesized or screened from large chemical libraries. Their structural features are designed to facilitate interaction with biological targets, such as enzymes or receptors, while also exhibiting favorable absorption, distribution, metabolism, and excretion (ADME) properties. The aim is to identify molecules that have a high probability of becoming effective and safe therapeutic agents.

The term is not a strict definition but rather a guiding principle. Molecules considered smallmoleculelike are generally characterized by a molecular weight under 500 Daltons, a logP (octanol-water partition coefficient) between 1 and 5, and a limited number of hydrogen bond donors and acceptors. These guidelines, often referred to as Lipinski's Rule of Five, are frequently used to assess the drug-likeness of a compound. By focusing on smallmoleculelike entities, researchers can increase the efficiency of drug discovery pipelines, reducing the number of compounds that fail in later, more expensive stages of development.