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

Abstract

Two new schemes for TcOJMo0~-separations fiom OH-and MOO: -media using polyethylene glycol (PEG)-based aqueous biphasic systems (ASS) have been developed. The two most important salt solutions in current -Tc-generator technologies, OH-and MOO: , also salt out PEG to form ABS. In liquidfliquid PEG-ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO; and back extraction into a salt solution. The strip solution can be the salt of an imaging agent (e.g., Na,HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. -TcOi can also be concentrated fiom a dilute load solution of ?MOO: in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with KJO, assures that all ?MOO:-is removed from the column and this is confirmed by a rapid drop in ?Mo activity by the fourth free column volume (fcv) of rinse. The T c O i is then eluted with water. This chromatographic separation affords 94% of the V c O ; activity in 5 fcv, with the y spectrum showing less than 2 x IO4 of the original %o activity.

Radioisotopic Purity of Sodium Pertechnetate 99mTc Produced with a Medium-Energy Cyclotron: Implications for Internal Radiation Dose, Image Quality, and Release Specifications

“…Therefore, the results reported here exemplify the less favorable energy region for 99m Tc production (24/19 MeV) and can serve as a reasonable worst-case approximation. Polyethylene glycol-based aqueous biphasic extraction chromatography resin was selected for separation because it is known to retain pertechnetate from industrial alkaline waste (14) and was reported for separation of medical 99m Tc (15). A range of other resins of the same nature, namely the Tentagel (Rapp Polymere) and ChemMatrix (PCAS BioMatrix) product lines, were tested recently by others and showed similar results (16,17).…”

Effects of speciation on partitioning of iodine in aqueous biphasic systems and onto ABEC® resins

“…4 plots D and D W values for iodide versus increasing concentration of (NH 4 ) 2 SO 4 , K 2 CO 3 , KHCO 3 (ABEC only), and NaOH in PEG-2000 ABS, and onto ABEC-5000. It is interesting to note that the trend for distribution ratios for a chaotropic anion such as pertechnetate increases with increasing |− G hyd | of the salting-out agent, [15,20] does not seem to hold true for iodide with the ABEC resin, i.e., iodide has a lower D W value in the K 2 CO 3 salt system, than in the (NH 4 ) 2 SO 4 system. However, as discussed earlier (Fig.…”

“…We have previously demonstrated this feature with quantitative partitioning of 99 TcO 4 − to the PEG-rich phase of several high ionic strength solutions [3]; a property which we have exploited in the removal of 99 TcO 4 − from simulants of the highly alkaline radioactive waste tanks at the Hanford, WA site [4] and from solutions of MoO 4 2− in caustic found in 99m Tc-generator technologies [15]. In addition, the similarities between TcO 4 − and ReO 4 − , has allowed development of effective separations strategies for ReO 4 − /WO 4 2− and ReO 4 − /MoO 4 2− [16], important separations in radiopharmacy and hydrometallurgy.…”

Separation of 97Ru from niobium target using PEG based aqueous biphasic systems

“…Polyethylene glycol (PEG) based aqueous biphasic systems (ABS) is a greener analytical technique compared to traditional solvent extraction system as both the phases in ABS are aqueous in nature [1]. ABS is formed when watersoluble polymer PEG and polymer like dextran, starch, polyvinyl alcohol, etc., with one another or PEG with certain inorganic salts like Na 2 SO 4 , (NH 4 ) 2 SO 4 , Na 2 HPO 4 , Na 2 CO 3 etc.…”