Abstract 2677: Comparison of different methods for radiochemical purity (RCP) control of 99mTc-tetrofosminin oncology.
Authors: Olivier Madar, Keyvan Rezaï, Emmanuelle Ledauphin, Eve Camps, Catherine Tainturier, Francois Lokiec
Journal: Cancer Research (2013)

Abstract Background : The 99mTc-tetrofosmin is a radiopharmaceutical used in oncology for scintigraphic quantification of the myocardial perfusion. 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 combined to hydrophilic impurities such as gluconate-99mTc and takes from 30 to 35 minutes. Alternative methods by planar or liquid chromatography have been developed (Whatman® (W) plate, Sep-Pak® or HPLC). The aim of our study is to evaluate each method versus the reference one. Methods : The reference method is a method using planar chromatography TLC SA tape, size 1 cm x 20 cm. Two marks were scored: one at 3 cm from the bottom indicates the deposit (10 μL of the preparation) and the other at 15 cm from the bottom the end of migration. Mobile phase was acetone: dichloromethane (65:35, v/v). The band marks were quantified by radioactive counting using a miniGITA® radiochromatograph (Raytest) equipped with a scintillation probe. The other planar chromatographic methods are W 1 (0.18 mm) and W 3MM (0.34 mm), the principle and the quantifying method are similar to reference method. SEP-Pak®(Waters) method uses a C18 chromatography column with 2 mobile phases (NaCl 0.9% and ethanol) and a sample volume between 25 to 50 μL. Activity was quantify with a calibrator CRC 25® (Capintec) The chromatographic system consisted in a Symmetry Shield® column RP18 5μm 100Å (Waters) with a gamma detector Gammaram® (Lablogic). Empower® software (Waters) is used for peak integration. The mobile phase flowing at a rate of 1.0 mL / min consisted in a mixture of acetonitrile and Titrisol® buffer (Waters) (40:60, v/v), the sample volumes were no more than 10 to 30 μL. Results : The RCP was measured simultaneously by the different methods with 30 preparations. For HPLC, mean RCP = 97.21%, σ= 2.178% [91.6%-99.63%]. For TLC SA, mean RCP = 97.99%, σ= 1.135% [94.31%-99.86%]. For Sep-Pak® mean RCP = 97.15, σ= 1.133 [94.96%-99.55%], For W 3 MM mean RCP = 99.11 σ= 0.3252 [98.28%- 99.81%], For W 1 mean RCP = 98.32 σ= 0.5677 [97.01%-99.23%]. The results obtained by these methods were compared using the Wilcoxon t test.α = 0.05. The RCP obtained by TLC SA and SEP-Pak® method are significantly different (p = 0.026). The RCP obtained by TLC SA and W 1 and 3 MM methods are also significantly different (p w1 = 0.041, p w3 &amp;lt; 0.0001). The RCP obtained by either TLC SA or HPLC method are not significantly different (p = 0.497) Conclusions : A new HPLC method was developed for the control of the RCP 99mTc-tetrofosmin. The other methods differ from RCP (reference method). Whatman methods overestimate RCP values versus TLC SA or HPLC method. This study allows us to improve the detection of the cardiotoxic side effects due to chemotherapy more quickly than TLC SA method and permits early prevention of toxicity by dose adjustment of anticancer drugs. Citation Format: Olivier Madar, Keyvan Rezaï, Emmanuelle Ledauphin, Eve Camps, Catherine Tainturier, Francois Lokiec. Comparison of different methods for radiochemical purity (RCP) control of 99mTc-tetrofosminin oncology. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2677. doi:10.1158/1538-7445.AM2013-2677