Evaluation of 99mTc-Ethambutol Radiopharmaceutical Using High Performance Liquid Chromatography with Radioactive Detector (Radio-HPLC)

99mTc-ethambutol is a radiopharmaceuticals used to determine the location of Mycobacterium
tuberculosis that causes TB disease. To prepare this radiopharmaceuticals, supporting compounds such
as mannitol as filler, SnCl2
as a reducing agent and sodium pyrophosphate as co-ligand are required
in addition to ethambutol and radionuclide compounds. The radiopharmaceuticals is made in the form
of a lyophilized kit without 99mTc radionuclides. The aim of this study was to determine the effect of
reducing agents on 99mTc-ethambutol preparation using the High Performance liquid chromatography
(HPLC) equiped with radiodetector (radio-HPLC) to the quality of radiopharmaceuticals. In the
previous study, the determination of radiochemical purity only used TLC by determining the amount of
impurities TcO2
and TcO4
-
. This study was carried out more profoundly by using radio-HPLC to ensure
the quality of radiopharmaceutical products. The test were performed using paper chromatography,
electrophoresis, radio-HPLC, and stability test of 99mTc-ethambutol radiopharmaceuticals. The results
showed that the radiopharmaceutical kit of ethambutol is performing good physical characterictics
and high radiochemical purity of 99mTc-ethambutol in analysis using radio-HPLC as well as paper
chromatography and electrophoresis. The retention time (tr
) of 99mTc-ethambutol were found at 7.97
minutes using UV and radioactive detector, C18 column, isocratic system using phosphate buffer 0.2 M
pH 7.4 and Acetonitrile (90 :10), flow rate 0.8 mL/min. The radiochemical purity of 99mTc-ethambutol
is still remain high (91.44 ± 0.92%) after 27 days of kit were made. From the results, it was concluded
that radio-HPLC analysis provides better information on radiochemical purity as well as chemical
purity of the labeling of 99mTc-ethambutol.
Keywords: 99mTc-ethambutol, Radio-HPLC, TB disease, Mycobacterium tuberculosis, Radiopharmaceuticals