Small molecule

As a low molecular weight compound (English small molecule ) is called in pharmacology and biochemistry, a class of drugs whose molecular mass about 800 g · mol -1 does not exceed. Due to their small size small molecules are after the Rule of Five partially able to penetrate into cells and to exert their effect. The currently approved drugs are for the most part low molecular weight molecules.

The English term small molecules used in pharmaceutical practice English speaking countries primarily for the delimitation of biologics, which are mostly are proteins and thus to very " large molecules ". In this sense small molecules called especially the classic pharmaceutical agents that - in contrast to biologics - can usually be described by a simple structural formula and chemically synthesized. Thus, the term small molecules comprises an extremely heterogeneous group of substances, which - in addition to their small size - not much in common with each other have.

These compounds have a variety of biological functions, such as signaling molecules, as tools in molecular biology, as a medicament, as pesticides, and more. You can naturally (eg secondary metabolites) or artificial (eg, antivirals ) and its origin both positive effects against diseases (eg drugs ) or adverse effects (eg, teratogens and carcinogens ) have.

A very small part of the small molecules ( about 2%) is able to cross the blood -brain barrier, so that some drugs on the basis of small molecules for depression, schizophrenia and insomnia may be effective. Also for the treatment of brain tumors and brain metastases win low molecular weight compounds in importance.