Technetium Tc 99m Sulfur Colloid Injection

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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Technetium Tc 99m Sulfur Colloid Injection is a sterile, colloidal dispersion of sulfur labeled with radioactive ^99mTc, suitable for intravenous administration.

Technetium Tc 99m Sulfur Colloid Injection contains not less than 90.0 percent and not more than 110.0 percent of the labeled concentration of ^99mTc as sulfur colloid expressed in megabecquerels (microcuries or millicuries) per mL at the time indicated in the labeling. It may contain chelating agents, buffers, and stabilizing agents. Other chemical forms of radioactivity do not exceed 8 percent of the total radioactivity.

[Note—Agitate the container before withdrawing the Injection into a syringe.]

1 Packaging and storage

Store in single-dose or multiple-dose containers.

2 Labeling

Label it to include the following, in addition to the information specified for Labeling 〈7〉, Labels and Labeling for Injectable Products: the time and date of calibration; the amount of ^99mTc as sulfur colloid expressed as total megabecquerels (microcuries or millicuries) and concentration as megabecquerels (microcuries or millicuries) per mL at the time of calibration; the expiration date; and the statement “Caution —Radioactive Material.” The labeling indicates that in making dosage calculations, correction is to be made for radioactive decay, and also indicates that the radioactive half-life of ^99mTc is 6.0 hours; in addition, the labeling states that it is not to be used if flocculent material is visible and directs that the container be agitated before the Injection is withdrawn into a syringe.

Radionuclide identification (see Radioactivity 〈821〉)—It meets the requirements of the test for Radionuclide identification under Sodium Pertechnetate Tc 99m Injection.

Bacterial Endotoxins Test 〈85〉 —The limit of endotoxin content is not more than 175/V USP Endotoxin Unit per mL of the Injection, when compared with the USP Endotoxin RS, in which V is the maximum recommended total dose, in mL, at the expiration date or time.

pH 〈791〉: between 4.5 and 7.5.

3 Radionuclidic purity

It meets the requirements of the test for Radionuclidic purity under Sodium Pertechnetate Tc 99m Injection.

4 Radiochemical purity

Place a measured volume of Injection, appropriately diluted, such that it provides a count rate of about 20,000 counts per minute, about 25 mm from one end of a 25- × 300-mm strip of chromatographic paper (see Chromatography 〈621〉), and allow to dry.

Develop the chromatogram over a suitable period by ascending chromatography, using dilute methanol (8.5 in 10), and air-dry. Determine the radioactivity distribution by scanning the chromatogram with a suitable collimated radiation detector. Not less than 92% of the total radioactivity is found as sulfur colloid (at the point of application).

5 Biological distribution

Inject intravenously between 0.075 MBq and 0.75 MBq (2 μCi and 20 μCi) of the Injection in a volume not exceeding 0.2 mL into the caudal vein of each of three 20-g to 25-g mice. Ten to 30 minutes after the injection, sacrifice the animals, and carefully remove the liver and lungs of each by dissection. Place each organ and remaining carcass in separate, suitable counting containers, and determine the radioactivity, in counts per minute, in each container in an appropriate scintillation well counter, using the same counting geometry. Determine the percentage of radioactivity in the liver and the lungs taken by the formula:

100(A/B)

in which A is the net radioactivity, in counts per minute, in the organ, and B is the total radioactivity, in counts per minute, in the lungs, liver, and carcass. Not less than 80% of the radioactivity is found in the liver and not more than 5% of the radioactivity is found in the lungs, in two of the mice.

6 Other requirements

It meets the requirements under Injections and Implanted Drug Products 〈1〉, except that the Injection may be distributed or dispensed prior to completion of the test for Sterility, the latter test being started on the day of final manufacture, and except that it is not subject to the recommendation on Container Content.

Assay for radioactivity(see Radioactivity〈821〉)—Using a suitable counting assembly, determine the radioactivity, in MBq (μCi) per mL, of Injection by use of a calibrated system.