2-[4-(1,2-diphenylbutyl)phenoxy]-N,N-dimethylethanamine
Chlorotoxin I-131 is investigated in clinical trials for treating brain cancer. Chlorotoxin I-131 binds to and reduces the activity of a matrix metalloproteinase (MMP) that regulates functioning of the chloride channels on cell membranes. Chlorotoxin is a small 36-amino-acid peptide that selectively binds to glioma cells but not normal brain parenchyma. It is a synthetic version of a neurotoxin isolated from the venom of the Giant Yellow Israeli scorpion Leiurus quinquestriatus. The synthetic version of this peptide has been manufactured and covalently linked to iodine 131 as a means of targeting radiation to tumor cells in the treatment of brain cancer. The selective effects of Chlorotoxin I-131 are regulated by its action on MMP2 receptors.