CTAP TFA, a potent and highly selective μ opioid receptor antagonist that effectively crosses the blood-brain barrier, exhibits a significant inhibition concentration (IC50) of 3.5 nM. It demonstrates extraordinary selectivity, being over 1200-fold more specific to μ opioid receptors than to δ opioid (IC50 = 4500 nM) and somatostatin receptors. This compound is primarily leveraged for researching L-DOPA-induced dyskinesia (LID) and opiate overdose or addiction [1] [2].