Crookesite Crookesite Crookesite is a selenide mineral composed of copper and selenium with variable thallium and silver. Its chemical formula is reported either as Cu(Tl,Ag)Se or (Cu,Tl,Ag)Se. It is formed by precipitation from hydrothermal fluids, and contains by mass: 16.3% Tl, 47.3% Cu, 2.9% Ag, and 33.6% Se. Crookesite is an opaque, bluish grey to pink toned brown metallic mineral crystallizing in the tetragonal system. It has a Mohs hardness of 2.5 to 3 and a specific gravity of 6.9. It was discovered in 1866 in Skrikerum, Sweden and named for Sir William Crookes (1832–1919), the discoverer of the element thallium.
CU-2010 and CU-2020 a substrate, due to its peptide-like properties. After intravenous infusion, CU-2010 is quickly cleared as it has a half-life of about 20 minutes (in rats and dogs). Polymerization and covalent attachment of polymer chains of polyethylene glycol (PEG) or pegylation results in the formation of CU-2020, which has a longer half-life of 45 minutes. The advantage of the short half-life of CU-2010 is that it allows it to work in an “on-off” mode, hence being able to adapt to the haemostatic situation of the moment. CU-2010 and CU-2020 have the ability to inhibit plasmin to a similar extent as aprotinin,