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New Technetium-99M Generator Technologies Utilizing Polyethylene Glycol-Based Aqueous Biphasic Systems

1997; Taylor & Francis; Volume: 32; Issue: 1-4 Linguagem: Inglês

10.1080/01496399708003234

1520-5754

Robin D. Rogers, Andrew H. Bond, Jian‐Hua Zhang, E. Philip Horwitz,

Chemical and Physical Properties in Aqueous Solutions

Abstract Two new schemes for TcO4 −/MoO4 2− separations from OH− and MoO4 2− media using polyethylene glycol (PEG)-based aqueous biphasic systems (ABS) have been developed. The two most important salt solutions in current 99mTc-generator technologies, OH− and MoO4 2−, also salt out PEG to form ABS. In liquid/liquid PEG-ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO4 − and back extraction into a salt solution. The strip solution can be the salt of an imaging agent (e.g., Na4HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. 99mTcO4 − can also be concentrated from a dilute load solution of 99MoO4 2− in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K2CO3 assures that all 99MoO4 2− is removed from the column, and this is confirmed by a rapid drop in 99Mo activity by the fourth free column volume (fcv) of rinse. The 99mTcO4 − is then eluted with water. This chromatographic separation affords 94% of the 99mTcO4 − activity in 5 fcv, with the γ spectrum showing less than 2 × 10−4 of the original 99Mo activity.