Abstract 2451: Development of a high performance liquid chromatography (HPLC) method for controlling the radiochemical purity (RCP) of 99mTc-tetrofosmin used in oncology

Abstract

Abstract Background: The 99mTc-tetrofosmin is a radiopharmaceutical used in oncology for scintigraphic quantification of the myocardial perfusion. The preparation of this drug is based on a complexation reaction of technetium 99 metastable (99mTc) with tetrofosmin. The reference method for quality control is thin layer chromatography, using TLC SA bands. This method is simple but only separates two types of impurities: free technetium and hydrolyzed technetium associated to hydrophilic impurities like gluconate-99mTc and takes from 30 to 35 minutes. This gluconate impurity gives a poor image quality and difficult interpretation issues. HPLC is a sensitive and specific method, it thus, has an interest in controlling RCP and identifying all impurities. Methods: The reference method is a method by planar chromatography TLC SA tape, size 1 cm x 20 cm. Two marks were scored: 3 cm from the edge to indicate the deposit (10 µL of the preparation) and 15 cm by the end of migration. Mobile phase was acetone: dichloromethane (65:35, v/v). The radioactive bands were quantified by counting the radioactivity using a radiochromatograph miniGITA® (Raytest) equipped with a scintillation probe. The chromatographic system consisted in a Symmetry Shield® column RP18 5μm 100Å (Waters) with a gamma detector Gammaram® (Lablogic). Empower® software (Waters) was used for peak integration. The mobile phase, at a rate flow of 1.0 mL / min, consisted of a mixture of acetonitrile (Waters) and titrisol® buffer (Waters) (40:60, v/v). The sample volumes injected were no more than 10 to 30 µL in order not to exceed 50,000 counts per second due to the risk of radioactive detector saturation. Results: The RCP was measured simultaneously by HPLC and reference method in 30 preparations. For HPLC, mean RCP = 97.21%, α= 2.178% [91.6%-99.63%]. For TLC SA, mean RCP = 97.99%, α= 1.135% [94.31%-99.86%]. The results obtained by both methods were compared using the Wilcoxon t test. The RCP obtained either by TLC SA or HPLC methods are not significantly different (p-value = 0,497, higher than in significance ≤ = 0.05) Conclusions: A new HPLC method was developed for the control of the RCP 99mTc-Tetrofosmin. This method is reliable, rapid, sensitive and easy to use when the equipment is available. It allows us to improve the detection of cardiotoxic side effects due to chemotherapy more quickly than TLC SA method and to prevent toxicity by dose adjustment of anticancer drugs. Although the HPLC method does not differ from TLC (reference method), HPLC provides additional information about the quality of the preparation (percentage of gluconate-99mTc). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2451. doi:1538-7445.AM2012-2451