Technetium Tc 99m Red Blood Cells 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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1 DEFINITION

Technetium Tc 99m Red Blood Cells Injection is a preparation of anticoagulated whole blood that is labeled with radioactive technetium (^99mTc). The cells are prepared for labeling by collection of an autologous sample of whole blood, which is anticoagulated with Heparin

Sodium or anticoagulant dextrose solution.

Technetium Tc 99m Red Blood Cells Injection contains NLT 90.0% and NMT 110.0% of the labeled concentration of ^99mTc as labeled blood cells expressed in megabecquerels (or in millicuries or microcuries) per milliliter at the time indicated in the labeling. It may contain anticoagulants, such as Heparin or anticoagulant citrate solution, chelating agents, stannous chloride, and sodium hypochlorite. Other chemical forms of radioactivity are NMT 10.0% of the total radioactivity. When derived from donor blood, its production and distribution are subject to federal regulations (see Radioactivity 〈821〉 and Biologics 〈1041〉).

[Caution—A strict aseptic technique must be followed for collection of the blood sample, along with the processing steps required to label it with ^99mTc. The blood samples must be labeled with the name of the patient and patient's identification code to prevent administration of the sample to other than the intended patient. In the event that donor blood is used, it must first be tested for viral contaminants and carefully typed and cross-matched to ensure compatibility with that of the recipient.]

2 IDENTIFICATION

A. Radionuclidic Identity

(See Radioactivity 〈821〉, Identification of Radionuclides.)

Acceptance criteria: Its gamma-ray spectrum is identical to that of a specimen of 99mTc that exhibits a major photopeak having an energy of 0.140 MeV.

Add the following:

B. Radiochemical Identity

Analysis: Examine the distribution of the radioactivity found in the Sample solution for the Radiochemical Purity test.

Acceptance criteria: The distribution of the radioactivity contributes to the identification of the preparation. (USP 1-Aug-2024)

3 ASSAY

Radioactive Concentration (Strength)

(See Radioactivity 〈821〉, Assay of Radionuclides.)

Analysis: Using a suitable counting assembly, determine the radioactivity, in megabecquerels (or microcuries) per milliliter, of the Injection by use of a calibrated system.

Acceptance criteria: 90.0%–110.0% of the labeled concentration of 99mTc at the time indicated in the labeling

4 PURITY

Radionuclidic Purity

(See Radioactivity 〈821〉.)

Analysis: Using a suitable counting assembly, determine the radioactivity of each radionuclidic impurity, in kilobecquerels per megabecquerel (microcuries per millicurie) of technetium 99m in the Injection by use of a calibrated system.

Acceptance criteria

For Injection prepared from technetium 99m derived from parent molybdenum 99 formed as a result of neutron bombardment of stable molybdenum: See Table 1.

For Injection prepared from technetium 99m derived from parent molybdenum 99 formed as a result of uranium fission—gamma- and beta-emitting impurities: See Table 2.

Table 1

^a Radioactivity of radionuclidic impurity/radioactivity of Tc 99m per administered dose of Injection at the time of administration.

^b Does not exceed 92 kBq (2.5 μCi) per administered dose of the Injection at the time of administration.

Table 2

^a Radioactivity of radionuclidic impurity/radioactivity of Tc 99m present at the time of administration.

^b Use a counting system appropriate for the detection of particulate radiations.

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Radiochemical Purity

Sample solution: Transfer 0.2 mL of the Injection to a centrifuge tube containing 2 mL of 0.9% sodium chloride solution. Centrifuge for 5 min, and carefully withdraw the diluted plasma by pipet.

Analysis: Measure the radioactivity in the plasma and red blood cells of the Sample solution separately in a suitable counter.

Calculate the percentage of 99mTc bound to the red blood cells in the portion of Injection taken: (USP 1-Aug-2024)

Result = [A_RBC /(A_RBC + A_P)] × 100

A_RBC = activity in the red blood cells

A_P = activity in the plasma

Acceptance criteria: NLT 90% of the 99mTc present in the Injection is bound to the red blood cells

5 SPECIFIC TESTS

Clarity and Color of Solution

Analysis: Observe the appearance and color of the Sample solution obtained as directed in the Radiochemical Purity test.

Acceptance criteria: The diluted plasma is clear and has a colorless to a very slight pink or yellow appearance. Samples that produce a distinctive red coloration are not acceptable for administration.

 pH 〈791〉: 5.5–8.0

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Bacterial Endotoxins Test 〈85〉: Meets the requirements. The Injection may be distributed or dispensed prior to completion of the test. (USP 1-Aug-2024)

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Sterility Tests 〈71〉: Meets the requirements. The Injection may be distributed or dispensed prior to completion of the test. (USP 1-Aug-2024)

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Other Requirements (USP 1-Aug-2024)

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in adequately shielded single-dose or multiple-dose containers, at controlled room temperature.

Labeling: Label the Injection to include the following, in addition to the information specified under Labeling 〈7〉, Labels and Labeling for Injectable Products: the patient's name and identification number; the type of anticoagulant used; the time and date of calibration; the amount expressed as total megabecquerels (or microcuries or millicuries) and concentration as megabecquerels (or microcuries or millicuries) per milliliter 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 h.