Dr. Julia Locke, EMEA
Targeted cancer treatment provides the best possible outcomes
Some cancer treatments can be non-discriminatory, causing damage to healthy tissues and lengthening the recovery time of the individual. It is important to give people the best possible outcome, and to minimise the side-effects of treatment that they receive. Targeted treatments are positive step forward towards this aim.
Targeted Radionuclide Therapy (TRT), or molecular radiotherapy employs radiopharmaceuticals, comprised of a radionuclide (radioactive atom) and cell-targeting molecule, which readily interacts with the malignancy, in order to diagnose and treat diseases such as cancer. The delivery of radionuclides to specific sites is much less damaging to healthy tissue than chemotherapy. Radiation is delivered in a specified dose, in the form of α, β−, and Conversion/Auger electron-emitters, to antigens or receptors and act by damaging tumours, at a genetic level, so that they are unable to spread.
New method of producing platinum radionuclides
In a recent study, Obata et al. (2019) provided details of a new method for producing platinum radionuclide, 191Pt, from an iridium target. There are challenges in producing radionuclides, which are succinctly explained in their paper. Obata et al. (2019) have addressed making the dissolution of irradiated iridium easier and demonstrated the chemical separation of platinum (IV) chloride and iridium (IV) chloride complexes through methods involving solvent extraction and ion exchange chromatography.
The researchers prepared and irradiated the target in a vertical beam irradiation system. The target then underwent dissolution. Chemical separation followed with selective reduction and solvent extraction and anion exchange chromatography, before final preparation of the Pt(IV) and Pt(II) products for use in the synthesis of platinum drugs.
Chemical separation was successfully achieved by reducing IrIVCl62- with acetaldoxime, to leave PtIVCl62- in solution. Further purification, to remove trace iridium species, was undertaken in an Omnifit® EZ Glass Column (12cm x 10mmid) connected to a peristaltic pump. The column was loaded with a 37–55 μm silica-based anion exchanger, followed by the PtIVCl62- solution, and a MeCN / HCl eluting agent. HPGe Gamma-ray spectrometry was used to analyse fractions in order to separate the platinum from the iridium. It was found that PtIVCl62- was strongly retained within the column whilst IrIVCl62- moved through with relative ease. As a result, a pure fraction was obtained.
Cole-Parmer products used in the research
Obata et al. (2019) recommend that anion exchange chromatography is performed relatively early in the process. These methods utilised an Omnifit EZ Glass Column and Peristaltic Pump, which can be purchased from Cole-Parmer.
The Diba® Omnifit EZ Glass Column is ergonomically designed, easy to use and are ideal for low- to medium-pressure applications and are resistant to many solvents used in liquid chromatography. The modular design gives you the flexibility to mix and match column sizes with different endpiece types to meet your specific requirements depending on whether media swell/contract or not. The columns are made from precision borosilicate glass which provides inertness, visibility, and performance. PEEK™ column threads support their multiple re-use, whilst superior frit placement provides good bed support and even distribution of sample and solvent flow. These columns are easy to repack and reuse due to their design and the accessories that are available.
The Peristaltic Pump of choice for this application would ideally come from the Masterflex® Ismatec® pumps that offer precise, repeatable and accurate dispensing at low flows of 0.0001 µL to 45 mL. Within this range are the IPC-N low-flow, high-accuracy models that can transfer 0.0004 mL to 11 mL per minute, which is more than ideal for pumping a dose of 0.5 to 1.0 mL/min as suggested by Obata et al. (2019). These multichannel programmable pumps feature planetary gears that drive eight stainless steel rollers in unison for smooth rotation and accurate liquid flow. The number of channels that are available are 4, 8, 12, 16, and 24. Click’n’go™ cartridges feature automatic occlusion for simplified use, fewer tubing changes, and reproducible results. Adjustable occlusion cartridges are available separately. Cartridges can be installed in one direction for low pulsation; or in the opposite direction for higher counter pressure. These models have remote control capabilities to allow operators to separate themselves from the procedure. Programming ensures that back-steps can be included to ensure drips are prevented.