Small Molecule Antagonists

Small molecule antagonists, or sometimes called blockers are substances that act against and block agonist-mediated effects. Antagonists themselves do not induce biological effects. Antagonists and agonists are key participants in the chemistry and pharmacology.

Small molecule antagonists can be classified into two categories according to whether they are reversibly competing with agonists. Competitive antagonists compete with agonists for the same binding site, and their binding is mutually exclusive. The activity of antagonist can be overcome when agonist concentration increases. From the perspective of therapeutics, the competitive antagonists have two significances. One is that the degree of inhibition of competitive antagonists depends on the concentration of antagonists. It is significant to adjust the dosage according to the concentration of the drug entering the body. The other one is that the clinical response to an antagonist depends on the concentration of the agonist binding to the receptor. Non-competitive antagonists can prevent the action without any effect on the binding of agonists. Unlike competitive antagonists, the activity of non-competitive antagonists cannot be overcome by increasing the concentration of agonists.

With the development of biology, pharmacology, biochemistry and chemistry, people have more reasonable methods of lead identification and disease intervention. Modern pharmaceutical research of small molecule antagonists generally focuses on specific proteins whose abnormal or excessive expression and/or function are related to the cause of human disease including autoimmune diseases, inflammatory diseases, infectious diseases, cancer, pulmonary diseases, etc.

Small molecule antagonists of proteins can be identified and developed as human pharmaceuticals. In the process of small molecule antagonist research and development, the most critical challenge is the choice of the protein target. Efficacy and technical feasibility of specific protein targets should be considered. Protein targets of small molecule antagonists mainly include enzymes, cell receptors and protein-protein interactions. Among them, small molecule antagonists of receptors are a notable example of pharmacologically driven lead discovery. However, targets of proteins involved in protein-protein interactions are considered to be the most challenging.

Mechanism of NMDA Receptor Inhibition and Activation. Figure 1. Mechanism of NMDA Receptor Inhibition and Activation. (Zhu, S., et al., 2016)

Creative Biolabs provides powerful risk-based preclinical data verification services for small molecule antagonist research and development to deal with data reproducibility crisis which is a big obstacle for drug research and development and may lead to failure and high risk of investment. We have extensive experience in different kinds of small molecule antagonists and different disease areas. Our services focus on target validation, hit validation, lead validation, safety assessment and efficacy evaluation. We can help our customers anticipate challenges and overcome barriers from protein targets to the safety and efficacy of drug candidates.

Creative Biolabs has deep understanding of the challenges and potential of small molecule antagonist candidates. As a global contract research organization with professional scientific team, advanced equipment and up-to-date technology, we offer fully compliant and trustworthy results in the timelines promised to our clients. We also offer our clients with project feasibility assessment through a comprehensive assessment of you drug candidates to help reduce investment risk.

Creative Biolabs understands that developing drug candidates requires tailored solutions at every stage. We can provide customized services according to your specific needs and offer solutions tailored for you. Our services will be of great benefit to you. Please feel free to contact us and to find out how our solutions help our clients with their small molecule antagonist projects.


  1. Zhu, S., et al., 2016. Mechanism of NMDA receptor inhibition and activation. Cell, 165(3), pp. 704-714.

For Research Use Only
Let's Get Started
Contact Us

Follow us on
Copyright © 2024 Creative Biolabs. All Rights Reserved.