Separation of Clinical Grade 188Re from 188W Using Polymer Embedded Nanocrystalline Titania

Mechanochemically synthesized mesoporous alumina: a smart new-generation sorbent for preparation of chromatographic 188W/188Re generator

Abstract

In an effort towards affordable availability of chromatographic 188W/188Re generators for widespread clinical use, we report the mechanochemical synthesis of mesoporous alumina as an advanced sorbent material for preparation of the generator. The synthesized material exhibits remarkably high sorption capacity (550 ± 12 mg W/g), which is adequate for preparation of clinical-scale generators using low specific activity (LSA) 188W produced in medium flux research reactors. Sorption of 188W in mesoporous alumina follows Freundlich adsorption isotherm and pseudo second order kinetics, indicating that the process is chemisorption. A clinical-scale (~ 14.0 GBq) 188W/188Re generator was developed and its performance was evaluated over a period of 6 months. Rhenium-188 could be consistently obtained from the generator with high yield (> 80%) and it met all the requirements for clinical use. The present strategy is expected to increase the scope of separation chemistry for availing clinical-grade 188Re for the benefit of millions of cancer patients world over.

Graphic abstract

Preparation and characterization of zirconium silico188W-tungstate as a base material for 188W/188Re generator

Zr:W:Si. The optimum gel was prepared using the molar ratio 1:1:7 at pH 8. The ZrSiW gel was investigated by FTIR, XRD, thermal analysis (TGA and DTA), FESEM, XRF, and NAA. Then, XRF and NAA techniques were used to estimate the proportion of the constituents of the gel according to the molecular formula [ZrO₂(Si(WO₄)₂)16H₂O]. ¹⁸⁸W/¹⁸⁸Re generator was prepared based on the selected ZrSi¹⁸⁸W gel, which gives the highest tungsten content (393.3 mg W/g gel) with 75 ± 3% elution yield of ¹⁸⁸Re. Quality control was studied on the ¹⁸⁸Re to make sure its validity for clinical applications.

Chemistry and radiochemistry of As, Re and Rh isotopes relevant to radiopharmaceutical applications: high specific activity radionuclides for imaging and treatment

Advances in production, separation, target recovery, and chelation chemistry of high specific activity radionuclides will promote new theranostic agent development.

Development of an electrochemical 188W/188Re generator as a technique for separation and purification of 188Re in radiopharmaceutical applications

In this study, a simple electrochemical procedure adaptable for using low specific activity ¹⁸⁸W for separation and purification of ¹⁸⁸Re from ¹⁸⁸W to obtain no carrier added (NCA) ¹⁸⁸Re is developed. The electrochemical parameters were optimized to maximize the ¹⁸⁸Re electrodeposition yield with minimal ¹⁸⁸W contamination. Two cycle electrolysis procedure was developed. The first electrochemical cell was used for separation of ¹⁸⁸Re and in the second electrochemical cell, separation and purification of ¹⁸⁸Re with >90% deposition yield of ¹⁸⁸Re and minimal contamination of ¹⁸⁸W (<10^-4%) was achieved. The overall electrodeposition yield of ¹⁸⁸Re was >90% with >99% radionuclidic purity and >99% radiochemical purity suitable for radiopharmaceutical applications. Furthermore, the performance of the generator remained consistent during a period of 69 days, one half-life of ¹⁸⁸W, when the electrochemical separation procedure was performed frequently, at least once in 5 days.

An overview of radioisotope separation technologies for development of 188W/188Re radionuclide generators providing 188Re to meet future research and clinical demands

Separation technologies for ¹⁸⁸W/¹⁸⁸Re radionuclide generators.

Preparation and evaluation of hydrous titanium oxide as a high affinity adsorbent for molybdenum (99Mo) and its potential for use in 99mTc generators

Hydrous titanium oxide was prepared and its affinity as an adsorbent for molybdenum ( 99Mo) and its potential for use in 99mTc generators were evaluated. Adsorption behavior of molybdate on hydrous titanium oxide was studied at boiling water bath temperature (∼100 °C) using radiotracer technique. Various parameters affecting the adsorption of molybdenum, such as pH, amount of molybdenum, incubation period etc. , were determined. Technetium-99m generators were prepared by adsorbing low specific activity Molybdenum-99 (∼230 mg) on 1 g hydrous titanium oxide. Elutions were carried out with normal saline. Performance of the generators, such as 99Mo breakthrough, titanium content, pH, elution profile, radiochemical purity and labeling efficiency of kits, was checked.

Nanoceria-PAN composite-based advanced sorbent material: a major step forward in the field of clinical-grade 68Ge/68Ga generator

The (68)Ge/(68)Ga generator has high potential for clinical positron emission tomography (PET) imaging. However, because of the unavailability of a suitable sorbent material, the commercially available (68)Ge/(68)Ga generators are not directly adaptable for the preparation of (68)Ga-labeled radiopharmaceuticals. In view of this, a new nanoceria-polyacrylonitrile (PAN) composite sorbent has been synthesized by decomposition of a cerium oxalate precursor to cerium oxide and its subsequent incorporation in PAN matrix for the development of a clinical grade (68)Ge/(68)Ga generator. The X-ray diffraction (XRD) studies and BET nitrogen adsorption technique revealed that nanocrystalline ceria had an average particle size of approximately 10 nm, surface area of 72 +/- 3 m(2)/g and an average pore size of 3.8 +/- 0.1 A. Investigation of the distribution ratio (K(d)) values for the prepared sorbent in 0.01 N HCl medium revealed the suitability of the sorbent for the quantitative retention of (68)Ge and efficient elution of clinical grade (68)Ga. A 370 MBq (10 mCi) (68)Ge/(68)Ga chromatographic generator was developed using this sorbent. (68)Ga could be regularly eluted from this generator with >80% elution yield. The eluted (68)Ga possess high radionuclidic purity (<1 x 10(-5)% of (68)Ge impurity), chemical purity (<0.1 ppm of Ce, Fe and Mn ions) and was amenable for the preparation of (68)Ga-labeled radiopharmaceuticals. The generator gave a consistent performance with respect to the elution yield and purity of (68)Ga over an extended period of 7 months.