A quantitative description of the compatibility of technetium-selective chromatographic technetium-99m separation with low specific activity molybdenum-99.

Technetium-99m generators employing a technetium-selective stationary phase are a chromatographic instrument developed for use with 99Mo having low specific activity (LSA); particularly, 99Mo produced by electron accelerators. This paper presents a mathematical description of technetium-selective chromatographic (TSC) 99mTc separation and analyzes its compatibility with LSA 99Mo. We developed a theoretical formula for TSC 99mTc separation by discretizing its pertechnetate selectivity, and validated it using an electron linear accelerator and activated carbon-based TSC (AC-TSC) 99mTc generators. We confirmed that the activity concentration of 99mTc obtained from a TSC 99mTc generator can be calculated directly from its input 99Mo activity regardless of the 99Mo specific activity. The formula corroborates that TSC 99mTc separation is compatible with LSA 99Mo, and has a practical application in estimating the number of TSC 99mTc generators required for 99mTc demand of interest.

A preliminary biodistribution study of [99mTc]sodium pertechnetate prepared from an electron linear accelerator and activated carbon-based 99mTc generator.

INTRODUCTION: Production of 99Mo/99mTc using an electron linear accelerator (linac) and activated carbon (AC)-based 99mTc generator (linac-AC) is an alternative approach to the conventional fission production of 99Mo/99mTc. As a preliminary investigation of the clinical applicability of a linac-AC-derived 99mTc radiopharmaceutical, the biodistribution of linac-AC-derived [99mTc]sodium pertechnetate ([99mTc]NaTcO4) was measured and compared against fission-derived [99mTc]NaTcO4 at one time point. METHODS: 99Mo was produced by irradiating nonenriched MoO3 targets with bremsstrahlung photons generated from 55.5-MeV linac electron beams. 99mTc was then separated and purified from the 99Mo using an AC-based 99mTc generator. Subsequently, biodistribution of the linac-AC-derived [99mTc]NaTcO4 in healthy female Slc:ICR mice (n = 6) was measured by dissection and compared with that of fission-derived [99mTc]NaTcO4 (n = 4) at 30 min after injection. RESULTS: The two types of [99mTc]NaTcO4 exhibited similar biodistribution in all the organs and tissues examined: the uptakes of [99mTc]NaTcO4 prepared from the linac-AC method and those prepared from the fission method were 138.9 ± 69.9%ID/g and 160.6 ± 49.2%ID/g in the thyroids, respectively, 33.4 ± 5.5%ID/g and 29.4 ± 9.1%ID/g in the salivary glands, respectively, and less than 10%ID/g in blood and all the other organs. No adverse effects were observed in the mice administered with either [99mTc]NaTcO4. CONCLUSION: The clinical applicability of linac-AC-derived [99mTc]NaTcO4 was suggested by its similar biodistribution with fission-derived [99mTc]NaTcO4 at one time point. Further biodistribution studies at multiple time points are encouraged to demonstrate the bioequivalence between linac-AC- and fission-derived [99mTc]NaTcO4.

Synergistic cloud point extraction behavior of aluminum(III) with 2-methyl-8-quinolinol and 3,5-dichlorophenol.

The cloud point extraction behavior of aluminum(III) with 8-quinolinol (HQ) or 2-methyl-8-quinolinol (HMQ) and Triton X-100 was investigated in the absence and presence of 3,5-dichlorophenol (Hdcp). Aluminum(III) was almost extracted with HQ and 4(v/v)% Triton X-100 above pH 5.0, but was not extracted with HMQ-Triton X-100. However, in the presence of Hdcp, it was almost quantitatively extracted with HMQ-Triton X-100. The synergistic effect of Hdcp on the extraction of aluminum(III) with HMQ and Triton X-100 may be caused by the formation of a mixed-ligand complex, Al(dcp)(MQ)2.

Synergistic effect of 3,5-dichlorophenol and trioctylphosphine oxide on the extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives.

The extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives (HA), such as 2-methyl-8-quinolinol (HMQ), 2-methyl-5-butyloxymethyl-8-quinolinol (HMO4Q), and 2-methyl-5-hexyloxymethyl-8-quinolinol (HMO6Q), from a weakly acidic solution into chloroform was studied in both the absence and presence of 3,5-dichlorophenol (Hdcp) and trioctylphosphine oxide (TOPO) as the synergists. Vanadium(V) was extracted with HA as VO(OH)(A)2 in the absence of synergists, and its extractability increased with an increase in the hydrophobicity of HA. Vanadium(V) was quantitatively extracted from the lower pH region upon the addition of Hdcp and TOPO as VO(OH)(A)2 x Hdcp and VO2(A)(TOPO), respectively. The enhancement of the synergistic effect of Hdcp on the extraction of vanadium(V) with HA increased in the following order: HMQ < HMO4Q < HMO6Q, as opposed to that of TOPO. This result was ascribable to the difference in the mechanisms of the occurrence of the synergistic effect by Hdcp and TOPO.