Quick methods are functional in clinical practice to ensure the fastest availability of radiopharmaceuticals. For this purpose, we investigated the radiochemical purity of the widely used99mTc-hydroxymethylene diphosphonate,99mTc-hexamethylpropyleneamine oxime, and99mTc-tetrofosmin by reducing time as compared with the manufacturer's method. Methods: We applied a miniaturized chromatographic method with a reduced strip development from 18 cm to 9 cm for all 3 radiopharmaceuticals. The specific support medium and solvent system of the manufacturer's methods was kept unchanged for99mTc-hydroxymethylene diphosphonate and99mTc-tetrofosmin, whereas for99mTc-hexamethylpropyleneamine oxime the instant thin-layer chromatography (ITLC) polysilicic gel (silicic acid [SA]) was replaced with a monosilicic gel (silicic gel [SG]) in the chromatographic system that uses methyl ethyl ketone as solvent. The method was applied and compared with the routine ITLC insert method in a total of 30 batches for each radiopharmaceutical. The precision of repeated tests was determined by comparison with the results of 10 replications on the same batch. Small volumes of concentrated99mTcO4 -, and99mTc-albumin nanocolloid were used to produce potential radiochemical impurities. Correlation between the quick methods and the insert methods was analyzed using a nonparametric 2-tailed test and a 2 · 2 contingency table with the associated Fisher exact test to evaluate sensitivity and specificity. A receiver-operating-characteristic analysis was performed to evaluate the best cutoff. Results: The percentage radiochemical purity of the quick methods agreed with the standard chromatography procedures.We found that99mTcO4 and colloidal impurities are not the only common radiochemical impurities with99mTc-tetrofosmin, and shortening of the ITLC strip with respect to the manufacturer's method will worsen system resolution and may produce inaccuracy. Conclusion: The miniaturized methods we described represent a fast and reliable alternative for99mTc-exametazime and99mTc-oxidronate quality control, with the upper cutoff for acceptable radiochemical purity values being 84% and 95%, respectively. For99mTc-tetrofosmin radiochemical purity testing, a longer strip as described in the standard method is warranted.
Miniaturized radiochemical purity testing for99mTc-HMPAO,99mTc-HMDP, and99mTc-tetrofosmin
Erba, Paola A.
2017-01-01
Abstract
Quick methods are functional in clinical practice to ensure the fastest availability of radiopharmaceuticals. For this purpose, we investigated the radiochemical purity of the widely used99mTc-hydroxymethylene diphosphonate,99mTc-hexamethylpropyleneamine oxime, and99mTc-tetrofosmin by reducing time as compared with the manufacturer's method. Methods: We applied a miniaturized chromatographic method with a reduced strip development from 18 cm to 9 cm for all 3 radiopharmaceuticals. The specific support medium and solvent system of the manufacturer's methods was kept unchanged for99mTc-hydroxymethylene diphosphonate and99mTc-tetrofosmin, whereas for99mTc-hexamethylpropyleneamine oxime the instant thin-layer chromatography (ITLC) polysilicic gel (silicic acid [SA]) was replaced with a monosilicic gel (silicic gel [SG]) in the chromatographic system that uses methyl ethyl ketone as solvent. The method was applied and compared with the routine ITLC insert method in a total of 30 batches for each radiopharmaceutical. The precision of repeated tests was determined by comparison with the results of 10 replications on the same batch. Small volumes of concentrated99mTcO4 -, and99mTc-albumin nanocolloid were used to produce potential radiochemical impurities. Correlation between the quick methods and the insert methods was analyzed using a nonparametric 2-tailed test and a 2 · 2 contingency table with the associated Fisher exact test to evaluate sensitivity and specificity. A receiver-operating-characteristic analysis was performed to evaluate the best cutoff. Results: The percentage radiochemical purity of the quick methods agreed with the standard chromatography procedures.We found that99mTcO4 and colloidal impurities are not the only common radiochemical impurities with99mTc-tetrofosmin, and shortening of the ITLC strip with respect to the manufacturer's method will worsen system resolution and may produce inaccuracy. Conclusion: The miniaturized methods we described represent a fast and reliable alternative for99mTc-exametazime and99mTc-oxidronate quality control, with the upper cutoff for acceptable radiochemical purity values being 84% and 95%, respectively. For99mTc-tetrofosmin radiochemical purity testing, a longer strip as described in the standard method is warranted.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
