CDK5 inhibitor 20-223 is primarily used in research settings to study the role of cyclin-dependent kinase 5 (CDK5) in various cellular processes. It is particularly valuable in neuroscience, where it helps investigate CDK5's involvement in neurodegenerative diseases such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis (ALS). By inhibiting CDK5 activity, researchers can better understand its impact on neuronal function, synaptic plasticity, and cell death pathways. Additionally, this inhibitor is utilized in cancer research to explore CDK5's role in tumor progression and metastasis, as aberrant CDK5 activity has been linked to certain cancers. Its application extends to drug discovery, where it serves as a tool for developing targeted therapies for diseases associated with CDK5 dysregulation.