Methionine C 11 Injection
» Methionine C 11 Injection is a sterile isotonic solution, suitable for intravenous administration of l[11C]methionine, in which a portion of the molecules are labeled with radioactive 11C. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of 11C expressed in MBq (or in mCi) at the time indicated in the labeling. It may contain preservatives and stabilizers.
Specific activity: not less than 37.0 GBq (1.0 Ci) per mmol.
Packaging and storage— Preserve in single-dose or multiple-dose containers that are adequately shielded.
Labeling— Label it to include the following: the time and date of calibration; the amount of 11C as methionine expressed as total MBq (or mCi) per mL at time of calibration; the expiration time and date; the name and quantity of any added preservative or stabilizer; and the statement “Caution—Radioactive Material.” The labeling indicates that in making dosage calculations, correction is to be made for radioactive decay, and states that the radioactive half-life of 11C is 20.4 minutes. Each container to hold 11C methionine shall be independently labeled to indicate lot number and batch number. The labeling states that a microbiological filter (0.22 µm) is to be in place to remove any possible particulate matter that could be carried through to the final product.
USP Reference standards 11
USP Endotoxin RS
Radionuclide identification (see Radioactivity 821)— Its gamma-ray spectrum is identical to that of a specimen of 11C in that it exhibits a positron annihilation peak at 0.511 MeV and possibly a sum peak of 1.022 MeV, dependent upon geometry and detector efficiency.
Bacterial endotoxins 85 It contains not more than175/V USP Endotoxin Unit per mL of the Injection, in which V is the maximum recommended total dose, in mL, at the expiration time.
pH 791: between 6.0 and 8.0.
Radionuclidic purity 821 Using a suitable gamma-ray spectrometer, determine the absence of radiation other than at 0.511 MeV, over a period of 20 minutes. Determine the half-life (20.41 minutes) by a suitable detector system.
Chemical purity—
Mobile phase— Prepare a filtered and degassed mixture of 0.008 M copper acetate and 0.017 M l-proline. Adjust with 0.030 M sodium acetate to a pH of 5. Make adjustments, if necessary (see System Suitability under Chromatography 621).
Standard solution— Dissolve an accurately weighed quantity of dl-methionine in Mobile phase and dilute quantitatively, and stepwise if necessary, to obtain a solution containing 0.1 mg per mL.
Test solution— Pipet a volume of Injection into a suitable container, and dilute with Mobile phase to obtain a solution containing about 0.1 mg per mL.
Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 15-cm column that contains packing L1. The flow rate is about 0.5 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative retention times are 1.0 for d-methionine and 2.4 for l-methionine; the resolution, R, between the d- and l-enantiomers is not less than 1.5; the column efficiency is not less than 1400 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2%.
Procedure— Inject a volume (about 10 µL) of the Test solution into the chromatograph, record the chromatogram, and measure the peak responses. Calculate the percentage of d-methionine in the portion of Injection taken by the formula:
100(ri / rs)
in which ri is the peak response for d-methionine, and rs is the sum of the responses of all of the peaks: not more than 4% of d-enantiomer is found.
Radiochemical purity— Proceed as directed under Chemical purity. The radioactivity of the main peak is not less than 98% of the total radioactivity measured.
Other requirements— It meets the requirements under Injections 1, except that the Injection may be distributed or dispensed prior to completion of the tests for Sterility 71 and Bacterial Endotoxins 85, these tests being started on the day of final manufacture, and except that it is not subject to the recommendation of Volume in container.
Assay for radioactivity 821 Using a suitable counting assembly (see Selection of a Counting Assembly), determine the radioactivity, in GBq (Ci) per mL, of the Injection by use of a calibrated system.
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Monograph Ravi Ravichandran, Ph.D.
Principal Scientific Liaison
(SM42010) Monographs - Small Molecules 4
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85 Radhakrishna S Tirumalai, Ph.D.
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(GCM2010) General Chapters - Microbiology
USP35–NF30 Page 2493
Pharmacopeial Forum: Volume No. 30(3) Page 811