Clioquinol is a broad-spectrum antibacterial with antifungal properties, bacteriostatic. It is used as an antifungal and antiprotozoal topical drug OTC product for treatment of human infections. Previousely was used for wide number of intestinal disorders including lambliasis, shigellosis, balantidiral dysentery and some forms of diarrheas. The physiologic effect of clioquinol is by increased histamine release and cell-mediated immunity. It is a member of a family hydroxyquinolines which inhibit certain enzymes related to DNA replication. It is a copper, iron and zink chelating agent. It is an organic molecule with a quinolinic acid as its apparent core which itself is a neurotransmitter. In large doses it possesses neurotoxicity and may induce neurological disease such as subacute myelo-optic neuropathy by creating copper deficiency that leads to zink excess. SMON (Sub-Acute-Myelo-Optical-Neuropathy) - a polio-like disease began as an epidemic in 1959 in Japan was believed to be a Clioquinol caused. Clioquinol is a standardized chemical allergen. It has been resurrected as a potential treatment for Alzheimer's disease since it perturbs metallo-chemistry of amyloid and clioquinol treatment has been shown to be beneficial in a mouse model of Alzheimer's disease.

PBT-1033, also known as PBT-2, is a neural protective agent potentially for the treatment of Alzheimer's disease and Huntington's Disease. PBT-1033 is a moderate-affinity 8-hydroxyquinoline transition metal-ligand that acts as a synthetic chaperone, re distributing copper, zinc, and iron from locations where they are abundant to subcellular locations where they might be deficient. Delivery of copper and zinc by PBT-1033 into the cytoplasm deactivates the kinase glycogen synthase kinase 3β and the phosphatase calcineurin, both potential targets for Huntington’s disease. In aged wild-type mice, PBT-1033 improves cognitive ability and markers of neuronal plasticity and function. In Alzheimer’s disease mouse models, PBT-1033 inhibits the accumulation of amyloid β, attenuates neuropathological effects of amyloid β, including amyloid-β-induced hyperphosphorylation of tau, and improves cognition. In a 12-week, phase 2a, randomized, double-blind, placebo-controlled trial in 78 individuals with mild Alzheimer’s dementia, PBT-1033 was safe and well tolerated and significantly reduced concentrations of amyloid β42 in CSF.