(131I) Meta-Iodobenzyl Guanidine Injection for Diagnostic Use
Iobenguane Injection for Diagnostic Use
Category. Diagnostic.
Description. A clear, colourless or slightly yellow solution. On standing the solution may darken as a result of the
effect of radiation. Radioactive concentration should be in the range of 0.25 to 1 mCi/ml.
(131I) Meta-Iodobenzyl Guanidine Injection for diagnostic use is a sterile, apyrogenic solution of 1-(3-[131I]
iodobenzyl) guanidine or its salts. It may contain a suitable buffer. It may also contain a suitable labelling catalyst
such as ionic copper and a suitable labelling stabiliser such as ascorbic acid. It may contain antimicrobial
preservatives.
(131I) Meta-Iodobenzyl Guanidine Injection for diagnostic use contains not less than 90.0 per cent and not more
than 110.0 per cent of the stated iodine-131 radioactivity at the date and time stated on the label.
Identification
A. Determine by gamma-ray spectrometry. The most prominent gamma photon of iodine-131 has energy of
0.365 MeV.
B. In the test for Radiochemical purity, the chromatogram obtained contributes to the identification of the
distribution of radioactivity in the preparation.
Tests
pH (2.4.24). 5.0 to 8.0.
Radioactivity assay. Measure the radioactivity using a suitable counting apparatus by comparison with a
reference solution of iodine-131 or by measurement in an instrument calibrated with the aid of such a solution.
Radionuclidic purity. Not less than 99.9 per cent due to iodine-131.
Determine by Gamma-ray spectrometry.
The spectrum obtained corresponds to the spectrum obtained with the reference solution of Iodine 131. Determine
the relative amounts of iodine-131, iodine-133, iodine-135 and other radionuclidic impurities present. Iodine-133
has a half-life of 20.8 hours and its most prominent gamma photons have energies of 0.530 MeV and 0.875 MeV.
Iodine-135 has a half-life of 6.55 hours and its most prominent gamma photons have energies of 0.527 MeV,
1.132 MeV and 1.260 MeV.
Examine the gamma ray spectrum of the preparation. The most prominent gamma photon has an energy of
0.364 MeV.
Radiochemical purity. Determine by liquid chromatography (2.4.14).
Test solution. The injection under examination.
Reference solution (a). A 0.1 per cent w/v solution of sodium iodide in the mobile phase.
Reference solution (b). A 0.02 per cent w/v solution of iobenguane sulphate RS in the mobile phase.
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Chromatographic system:
a stainless steel column 25 cm x 4.0 mm packed with silica gel (5 µm),
mobile phase. a mixture of 1 volume of an 8.0 per cent w/v solution of ammonium nitrate in carbon dioxide-free
water, 2 volumes of dilute ammonia and 27 volumes of methanol,
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flow rate. 1.0 ml per minute,
a suitable radioactivity detector,
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a spectrophotometer set at 254 nm,
injection volume 10 µl
Inject the test solution, reference solution (a) and (b). In the chromatogram obtained with the test solution not less
than 94 per cent of the radioactivity of the chromatogram is found in the peak corresponding to iobenguane. Not
more than 5 per cent of the radioactivity is found in the peak corresponding to iodide and not more than 1 per cent
of the radioactivity is found in other peaks.
Sterility (2.2.11). Complies with the test for sterility as described in general chapter on Radiopharmaceutical
preparation. The injection may be released for use before completion of the test.
Bacterial endotoxins (2.2.3). Less than 175/V IU/ml, V being the maximum recommended dose in milliliters.
Storage. Store frozen at <0oC with adequate shielding
Labelling. The label states in addition to the information specified under injections (1) the amount of 131I as total
megabecquerels (millicuries) and concentration as megabecquerels (millicuries) per ml at the time of calibration
(2) the expiration date (3) the statement “Caution—Radioactive Material.”