Dose calibrator and gamma counter

Abstract

To ensure that pharmaceutical products have and maintain the structure, identity, purity, concentration, potency and safety characteristics required for their use, there is a set of standard procedures called Good Manufacturing Practices (GMP). In Brazil, the National Sanitary Surveillance Agency (ANVISA) regulates the GMP production of medicines through RDC17/2010 and for radiopharmaceuticals through RDC 63/2009 and 38/2008, to ensure their safe and correct use in commercial production and nuclear medicine services, respectively. Most 99mTc radiopharmaceutical monographs have biological distribution specifications. Using invasive method, 99mTcradiopharmaceuticalsare assessed by the injection into animals of defined strains and the radioactivity (as percentage of retainedor injected dose -%RDor%ID)ismeasured in specified organs. Technetium-99m Sestamibi radiopharmaceutical (99mTc-2-methoxy-isobutyl-isonitrile; 99mTc-sestamibi; MIBI-TEC®) monograph is related in USP 41, but the biological distribution assay is not included. At IPEN, the biodistribution test is performed as established in the Radiopharmaceutical Quality Control Manual of ARCAL XV (1999) - International Atomic Energy Agency (IAEA), for each batch. The objective of this work is to compare MIBI-TEC®biodistribution results using dose calibrator and gamma counter with sodium iodide detector by measuring the radioactivity in the organs. Three batches of MIBI-TEC®were used and 1 vial of lyophilized reagent (LR) was labeled with 5-10 mCiin 1-3 mL of 99mTc eluate. 200-300 μCi in 0.2 mLwereinjected in 3 Balb-Cmice. After 30 minutes of biodistribution, heart, lung, muscle, liver, paw, column and tail were withdrawn, weighed and radioactivity was measured in dose calibrator and gamma counter (μCi andcpm, respectively). %ID/g ratio in the organs of interest was calculated using the data obtained by both equipment and the results were compared. No significant differences were observed and it was possible to conclude that either a dose calibrator or a gamma counter can be used in the routine of quality control.