Sodium Fluoride (18F) Injection
Category. Diagnostic
Description. A clear, colourless solution. Sodium Fluoride (18F) Injection is a sterile solution containing
fluorine-18 in the form of sodium fluoride. It may contain carrier fluoride and a suitable buffer.
Sodium Fluoride (18F) Injection contains not less than 90.0 per cent and not more than 110.0 per cent of the
declared fluorine-18 radioactivity at the date and time stated on the label. Fluorine in the form of fluoride is not
more than 4.5 mg per maximum recommended dose, in milliliters.
Radiochemical preparation. The radionuclide fluorine-18 is most commonly produced by proton irradiation of
water enriched in oxygen-18. Fluorine-18 in the form of fluoride is recovered from the target water, generally by
adsorption and desorption from anion-exchange resins or electrochemical deposition and redissolution. If the
oxygen-18 enrichment is <95%, care is taken to ensure that nitrogen-13 formed from oxygen-16 is allowed to
decay for 30 min (three T ½) before processing. Water with oxygen-18 enrichment <80% should not be used.
Identification
A. Determine by gamma-ray spectrometry. The only gamma photons have an energy of 0.511 MeV and,
depending on the measurement geometry, a sum peak of 1.022 MeV may be observed.
B. Complies with test B for radionuclidic purity.
C. In the test for radiochemical purity by TLC, the principal peak in the radiochromatogram obtained with the
test solution is similar in retention time (remains at point of spotting) to the principal peak in the TLC obtained
with the reference solution.
Tests
pH (2.4.24). 5.0 to 8.5.
Radioactivity Assay. Radioactivity of an aliquot of Test Solution is assayed using precalibrated radioactivity
dose calibrator as described in measurement of radioactivity. It is expressed as MBq(mCi) in volume V ml at a
particular time and date.
Radionuclidic purity. Determine by gamma-ray spectrometry.
A. Determine by gamma-ray spectrometry using Sodium Iodide (Thallium) detector or Semiconductor detector.
The only spectrum is concordant with that of gamma photons have energy of 0.511 MeV and, depending on the
measurement geometry, a sum peak of 1.022 MeV may be observed.
B. The amount of Fluorine-18 and radionuclidic impurities with a half life longer than 2 hours. For the detection
and quantification of impurities, retain the preparation under examination for minimum 24 hour to allow the
fluorine-18 to decay to a level which permits the detection of impurities. The total radioactivity due to
radionuclidic impurities is not more than 0.1 per cent. The preparation may be released for use before
completion of the tests.
Radiochemical purity. Determine by liquid chromatography (2.4.14)
The test must be completed before release of the product.
Test solution. The injection under examination
[18F] fluoride, as described in the test for fluoride. If necessary, dilute the test solution with water to obtain a
radioactivity concentration suitable for the radioactivity detector. Not less than 98.5 per cent of the radioactivity
is found in the peak corresponding to [18F] fluoride.
Fluoride. Determine by liquid chromatography (2.4.14).
Test solution. The injection under examination.
Reference solution. Dissolve 10 mg of sodium fluoride in a volume equivalent to the maximum recommended
dose in milliliters of water.
Chromatographic system
- a stainless steel column 25 cm × 4 mm, packed with anion-exchange resin (10 µm),
- column temperature. between 20° and 30°,
- mobile phase: 0.1 N sodium hydroxide, protected from atmospheric carbon dioxide,
- flow rate. 1 ml per minute,
- spectrophotometer set at 220 nm,
- radioactivity detector connected in series,
- injection volume. 20 µl.
Inject the reference solution. The test is not valid unless the signal-to-noise ratio is not less than 10 for the
principal peak and the retention time of fluoride is not less than 3 times the hold-up time. In the chromatogram
obtained with the spectrophotometer the peak due to fluoride is not more than the area of the corresponding
peak in the chromatogram obtained with the reference solution (4.52 mg/V).
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). Not more than 175/V IU/ml, V being the maximum recommended dose in
milliliters. The test must be completed before release of the preparation.
Storage. Store in sterile and endotoxin free containers either as a single-dose or multiple-doses. The containers
should be adequately shielded for radioactivity.
Labelling. The label states (1) the maximum recommended dose in milliliters (2) the date of calibration (3) the
amount of 18F as fluoride anion expressed in megabecquerels (microcuries or millicuries) per ml at the time of
calibration (4) the expiration time and date (5) the statement “ Caution- Radioactive Material” and “do not use if
cloudy or if it contains particulate matter” (6) in making dosage calculations, correction is to be made for
radioactive decay (7) radioactive half life of 18F is 109.7 minutes.