EXPERIMENTAL BIODISTRIBUTION STUDIES OF TC-99M-RECOMBINANT HUMAN SERUM-ALBUMIN (RHSA) - A NEW-GENERATION OF RADIOPHARMACEUTICAL

Recombinant human serum albumin (rHSA) produced by cultured fermentati on has been prepared in the form of microcapsules nominally 3-5 mu m i n diameter and radiolabelled with technetium-99m following reduction w ith stannous chloride. Radiochemical purity was assessed by chromatogr aphy on instant thin-layer chromatography and found to be greater than 90%. No evidence of aggregation was seen by microscopic examination. Imaging biodistribution studies in New Zealand white rabbits demonstra ted targeting to the liver or lung, respectively, depending upon the s ize and surfactant properties of the microcapsules. This communication is the first to show scintigraphic studies using Tc-99m-labelled rHSA with the potential for lung, liver and cardiovascular imaging and dem onstrates that recombinant DNA technology offers an important new sour ce of materials suitable for use as radiopharmaceuticals without the n eed for pooled human blood products.