New technetium-99m generator technologies utilizing polyethylene glycol-based aqueous piphasic systems

Two new schemes for TcO4-/MoO42- separations from OH- and MoO42- 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 MoO42-, 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 99MoO42- in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K2CO3 assures that all 99MoO42- 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 y spectrum showing less than 2 x 10-4 of the original 99Mo activity