Indium In 111 Chloride Solution

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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Indium Chloride (¹¹¹InCl₃).

Indium (¹¹¹In) trichloride

CAS RN^®: 10025-82-8.

Indium In 111 Chloride Solution is a sterile, nonpyrogenic solution of radioactive indium (¹¹¹In) in dilute hydrochloric acid suitable for the radiolabeling of proteins such as monoclonal antibodies, peptides, or small biologically active organic molecules. The concentration of acid and ¹¹¹In per mL of Indium In 111 Chloride Solution may require adjustment for the specific antibody or peptide being labeled. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of ¹¹¹In expressed as megabecquerels (or millicuries) per mL at the time indicated in the labeling. Other chemical forms of radioactivity do not exceed 10.0 percent of the total radioactivity.

[Note-Indium In 111 Chloride Solution is generally recommended for use with specific antibodies or peptides. Consult the product labeling for recommendations and applications for radiolabeling.]

Specific activity: not less than 1.85 gigabecquerels (50 millicuries) per µg of indium at the date and time of calibration.

Packaging and storage-Preserve in single-unit containers at controlled room temperature.

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 ¹¹¹In as labeled chloride expressed as total megabecquerels (or millicuries) and the concentration as megabecquerels per mL (or as millicuries per mL) on the date and time of calibration; the expiration date; the statement, “Not for direct administration. Use only as an ingredient for radiolabeling;” 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 ¹¹¹In is 67.3 hours.

Identification-Add 1 drop of it to 2 drops of 0.1 M silver nitrate in a glass test tube: a white precipitate is formed (presence of chloride).

BACTERIAL ENDOTOXINS TEST 〈85〉-It contains not more than 175/V USP Endotoxin Unit per mL, in which V is the maximum recommended total dose, in mL, at the expiration date or time.

Acidity-Pipet 20 µL of Solution into a plastic tube containing 1 drop of bromocresol green, and titrate with 0.0025 N sodium carbonate to a blue endpoint. Calculate the acidity of the Solution by the formula:

0.0025V_T/ 20

in which V_T is the volume of titrant consumed: the molarity of the Solution is between 0.035 and 0.045.

RADIONUCLIDE IDENTIFICATION 〈821〉—Its gamma-ray spectrum is identical to that of a specimen of ¹¹¹In that exhibits major photopeaks having energies of 0.171 and 0.245 MeV.

Radionuclidic purity (see Radioactivity 〈821〉)—Using a suitable counting assembly, determine the radioactivity of each radionuclidic impurity, in kBq per MBq (µCi per mCi) of ¹¹¹In, in the Solution by use of a calibrated system as directed under Radioactivity 〈821〉.

INDIUM 110M-The limit of ^110mIn is 3 kBq per MBq (or 3 µCi per mCi) of ¹¹¹In. The presence of ^110mIn in the Solution is demonstrated by a characteristic gamma-ray spectrum with prominent photopeaks having energies of 0.66 and 0.91 MeV. ^110mIn decays with a half-life of 4.9 hours.

INDIUM 114M-The limit of ^114mIn is 3 kBq per MBq (or 3 µCi per mCi) of ¹¹¹In. ^114mIn is quantified by counting the beta emissions of ground state ¹¹⁴In with a beta-liquid scintillation counter having a high-energy channel set to discriminate against all counts arising from ¹¹¹In.

Zinc 65-The limit of ⁶⁵Zn is 3 kBq per MBq (or 3 µCi per mCi) of ¹¹¹In. The presence of ⁶⁵Zn in the Solution is demonstrated by a characteristic gamma-ray spectrum with a prominent photopeak at 1.116 MeV. ⁶⁵Zn decays with a radioactive half-life of 243.9 days.

1 Radiochemical purity

Adsorbent: instant thin-layer chromatography (ITLC) strips (2.5 cm × 10 cm).¹

Test solution-Dispense about 50 µL of Solution into 1 mL of 0.05 M hydrochloric acid, taking care to use polypropylene tips prewashed in 0.05 M hydrochloric acid for all dispensings.

Application volume: 2 µL. The amount of ¹¹¹In spotted should be between 0.5 µCi and 30 µCi as of the day of the test.

Developing solvent system: a mixture of a 1 in 10 solution of ammonium acetate and methanol (1:1).

Procedure-Proceed as directed for Thin-Layer Chromatography under Chromatography 〈621〉. Examine the plate with an appropriate scanner, and determine the percentage of radiochemical purity of the Test solution. The indium chloride will remain at the origin. Not less than 95% of indium is present as ionic indium.

2 Chemical purity

Copper-Determine the copper, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the copper, as directed by the manufacturer of the instrument used, and measuring the absorbance at 324.8 nm against a standard.

Nickel-Determine the nickel, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the nickel, as directed by the manufacturer of the instrument used, and measuring the absorbance at 232.0 nm against a standard.

Cadmium-Determine the cadmium, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the cadmium, as directed by the manufacturer of the instrument used, and measuring the absorbance at 228.8 nm against a standard.

Lead-Determine the lead, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the lead, as directed by the manufacturer of the instrument used, and measuring the absorbance at 217.0 nm against a standard.

Mercury-Determine the mercury, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the mercury, as directed by the manufacturer of the instrument used, and measuring the absorbance at 253.7 nm against a standard.

Iron-Determine the iron, in µg per mL, in the Solution by atomic absorption spectrometry (see Atomic Absorption Spectroscopy 〈852〉), using a graphite furnace to volatilize the iron, as directed by the manufacturer of the instrument used, and measuring the absorbance at 248.3 nm against a standard.

Zinc-Prepare a zinc stock solution in dilute hydrochloric acid (1 in 100) having a concentration of 1 µg of zinc per mL. Pipet 10 mL of the zinc stock solution into a 100-mL volumetric flask, dilute with water to volume, and mix to obtain a solution having a concentration of 0.1 µg of zinc per mL (Standard solution A). Pipet 20 mL of the zinc stock solution into a 100-mL volumetric flask, dilute with water to volume, and mix to obtain a solution having a concentration of 0.2 µg of zinc per mL (Standard solution B). Pipet 0.1 mL of Indium Chloride In 111 Solution into a 10-mL volumetric flask, dilute with water to volume, and mix to obtain the test solution. Determine the absorbances of the Standard solutions and the test solution at the zinc emission line at 213.9 nm with an atomic absorption spectrophotometer (see Atomic Absorption Spectroscopy 〈852〉) equipped with a zinc hollow-cathode lamp and an air-acetylene flame, using water as the blank. Determine the quantity of zinc, in µg per mL, in the Solution.

The composite total metal ion content is not greater than 1.0 µg per mL.

Other requirements-It meets the requirements under Injections and Implanted Drug Products 〈1〉, except that the Solution may be distributed or dispensed prior to completion of the test for Sterility Tests 〈71〉, 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 (or in microcuries or millicuries) per mL, of the Solution, by the use of a calibrated system.

¹ Type SG impregnated glass microfiber sheet (Gelman Sciences, Ann Arbor, MI).