PFI-90 is primarily used in research settings as a selective antagonist for the P2X7 receptor, which plays a role in inflammation and immune response. It is utilized to study neuroinflammatory processes, particularly in models of neurodegenerative diseases such as Alzheimer's and Parkinson's. Due to its ability to cross the blood-brain barrier, PFI-90 is valuable in investigating central nervous system inflammation and the role of purinergic signaling in disease progression. It has also been applied in pain research, helping to elucidate the mechanisms of chronic pain involving microglial activation. Its selectivity makes it a useful tool compound in pharmacological studies aiming to validate P2X7 as a therapeutic target.