H6phospa-trastuzumab: bifunctional methylenephosphonate-based chelator with 89Zr, 111In and 177Lu.

ABSTRACT: The acyclic chelator H6phospa and the bifunctional derivative p-SCN-Bn-H6phospa have been synthesized using nosyl protection chemistry and evaluated with (89)Zr, (111)In, and (177)Lu. The p-SCN-Bn-H6phospa derivative was successfully conjugated to trastuzumab with isotopic dilution assays indicating 3.3 ± 0.1 chelates per antibody and in vitro cellular binding assays indicating an immunoreactivity value of 97.9 ± 2.6%. Radiolabeling of the H6phospa-trastuzumab immunoconjugate was achieved with (111)In in 70-90% yields at room temperature in 30 minutes, while (177)Lu under the same conditions produced more inconsistent yields of 40-80%. Stability experiments in human serum revealed the (111)In-phospa-trastuzumab complex to be 52.0 ± 5.3% intact after 5 days at 37 °C, while the (177)Lu-phosp

SUBMITTER: Price EW 

PROVIDER: S-EPMC3872121 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature