COST-EFFECTIVE QUALITY CONTROL METHOD FOR RADIOCHEMICAL PURITY OF 99mTC-TECTROTYD USED IN A HOSPITAL RADIOPHARMACY UNIT
Keywords:Quality control, Radiochemical purity, Instant Thin Layer Chromatography Medium (ITLC), 99m Tc-Tektrotyd
The new Radiopharmacy in Nuclear Medicine department in the Hospital and University Service of Kosovo apply the policy that all products administered into the human body, especially the new one are safe and show a constant high quality in producing the required effects. To ensure the efficacy of radiopharmaceuticals prepared at department in the Hospital and University Service of Kosovo, we introduced a cost-effective routine chromatographic method.
The radiochemical purity (RCP) of 99m-Technetium labelled radiopharmaceuticals (RP) is important to ensure optimal scintigraphic image quality. In a new hospital radiopharmacy unit it may not be possible to use compendial analytical methods or expensive equipment for radiochemical purity analysis, but all radiochemical analysis methods should however be validated against compendial or otherwise proven methods.
Our goal was to optimize the radiolabeling protocol for the regular use of 99m Tc-Tektrotyd and to establish chromatographic method for quality control after labelling as a part of our daily diagnostic procedures for assessment of NET patients labelled with 99m-Technetium was for the first time used to identify medical problems related to overexpression of somatostatin receptors, particularly subtype 2 and, to a lesser extent subtype 3 and 5.
Methods: Tektrotyd or HYNIC – (D-Phe1, Thyr3-Octreotide) trifluoroacetate (Polatom) radiopharmaceutical were reconstituted with about 2 000 MBq of freshly eluted sodium pertechnetate as described by the manufacturer and spiked with eluate of the same generator to obtain a range of impurity concentrations. Samples of technetium- 99m Tektrotyd were spotted on 1x15 cm ITLC-SG strips and developed in appropriate mobile phases described by the manufacturer. Each strip was immediately cut into 30 pieces of 0.5cm and the radioactivity of each piece was measured in a dose calibrator (Capintec,Inc).
The percentage of RCP for each ITLC strip was calculated using the total the radioactivity and the radioactivity from each segment as the total present radioactivity from which the basic radioactivity was subtracted. The present plotted radioactivity in the obtained peaks corresponded to the distribution of radioactivity, i.e. to the present complex of 99mTc Tektrotyd.
Results and Discussion: The proposed method proved to be accurate and precise within the RCP range of approximately 90% to 100% in comparison of the producer requirements.
Conclusion: The proposed method is suitable as a reliable low-cost method for limited resource settings and small hospital radiopharmacy unit.
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