Mechanism of Action (MOA) Studies: Understanding Molecular Targets and Identifying Proteins plus Activated Pathways
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 or MOA studies 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.
MOA Studies: Accelerating Drug Evolution
A clear understanding of the mechanism of action of drug compounds is necessary for drug development and prevents failure at a later stage in the approval process. MOA studies help determine the clinical safety and act as a benchmark for newer drugs before their release in the market.
There are several reasons to understand the mechanism of action, a few of which are explained below:
- MOA studies allow scientists to identify how cells will respond to a drug compound used to treat a specific disease. Specifically, these studies allow for the identification of off-target pathways that may be activated by the drug compound.
- Drug pathways and subsequent reactions can be effectively monitored to improve dosing.
- Drug compound combinations can be identified to reduce the chance of drug resistance. The combination of drugs can effectively inhibit multiple targets with a single dose.
- Drug compounds exhibiting the ability to trigger a pharmacological response or disrupt the cytoplasmic membrane after forming a complex (DR complex) with its receptor confer selectivity of action. A clear understanding of a drug compound and corresponding reaction at the receptor site helps in developing new drugs with similar interactions.