The mechanism of action of a small molecule therapeutic gets clarified by studying the biochemical reactions that lead to its pharmacological effect. Mechanism of action studies or MOA clinical trial are used to achieve a deeper understanding of molecular targets and identify proteins plus activated pathways in the presence of a small molecule.
The MOA can occur on the cell membrane, within the cell, or outside the cell. Since molecular targets bind to receptors, enzymes, or ion channel at the target site, the MOA can either be receptor mediated or non-receptor mediated. A receptor mediated event occurs when a drug substance binds with its receptor and produces a drug receptor complex that triggers a biological response. A non-receptor mediated pathway occurs when a drug substance activates biological reactions through other mechanisms. Typically, chemical and physical actions such as chelation and osmosis are used to determine the relevant therapeutic impact.