[Purification of Cu-67 and Macrocyclic chelates for targeted therapy]. DOE annual report, 1993--94

{sup 67}Cu produced at the Brookhaven Linac Isotope Producer (BLIP) is purified from zinc target material and coproduced radioisotopes of cobalt, chromium, nickel, and gallium by a multi-step extraction process. This procedure introduces applicable amounts of cold copper into the sample, lowering the specific activity of the {sup 67}Cu. Because of this, the {sup 67}Cu produced at BLIP is not of high enough activity for use in radioimmunotherapy procedures. It is their goal to develop a procedure with which to purify {sup 67}Cu from the other radioisotopes produced, while at the same time minimize the amount of cold copper introduced into the system. There are two different approaches that they devised for the purification of {sup 67}Cu. They are an extraction method similar to what is used at Brookhaven already, and a copper affinity column. Bifunctional macrocyclic chelates have been developed to conjugate metals to antibodies, and metal chelated antibodies have been shown to have slower clearance from the tumor than iodinated antibodies. This provides a mechanism for increasing tumor radiation dose and the therapeutic index. Conditions for {sup 67}Cu radiolabeling of TETA immunoconjugates have been optimized, leading to rapid, quantitative complexation of metal binding sites, further contributing to high radioactive yield and to the routine production of {sup 67}Cu radiolabed immunoconjugates of therapeutic quality