Pharmacokinetics of 68Ga-NODA-aminoglucose in mice with Ehrlich carcinoma

The clinical application of Positron Emission Tomography (PET) is growing in Russia. To increase the accessibility of PET-procedures for the general public, the development of cost-effective radiotracers has become of particular importance. The paper presents results of the study of pharmacokinetic properties of the new compound contained based on NODA-aminoglucose and generate radionuclide gallium-68 (68Ga-NODA-AG). Intact outbred mice and mice with subcutaneously inoculated Ehrlich carcinoma were taken in the study. Concentration of 68Ga-NODA-AG was measured by direct radiometry. The same method was used for calculation of biological and effective half-lives of the radiopharmaceutical. Binding efficacy of 68Ga with NODA-AG was above 95%. The content of radiochemical impurities was less than 5%. Specific activity of 68Ga-NODA-AG in the tumor reduced from 3.19 %/g in 5 minutes after the radiotracer administration to 0.93 %/g, 0.34 %/g and 0.31 %/g in 1, 2, 3 hours respectively. Because an increased amount of radioactivity is accumulated in the tumor as compared with healthy tissues and organs the rate of 68Ga-NODA-AG clearance from the tumor tissue was relatively low. The compound was cleared by renal route. It should be stressed that 68Ga-NODA-AG concentration in the brain and the heart was low. Accumulation of radioactivity in tumor-bearing mice was lower than in intact animals mainly at early stages of the study. Biological and effective half-lives of the radiopharmaceutical in all organs and tissues except for the brain were higher in tumor-bearing mice than in intact animals. The obtained results allow making the following conclusion: the pharmacokinetic properties of 68Ga-NODA-AG are optimal for diagnostic radiopharmaceuticals.