Cyanocobalamin Co 57 Oral Solution
Vitamin B12-57Co [41559-38-0; 13115-03-2].
» Cyanocobalamin Co 57 Oral Solution is a solution suitable for oral administration, containing Cyanocobalamin in which a portion of the molecules contain radioactive cobalt (57Co) in the molecular structure. Cyanocobalamin Co 57 Oral Solution contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of 57Co as cyanocobalamin expressed in megabecquerels (microcuries) per mL at the time indicated in the labeling. The cyanocobalamin content is not less than 90.0 percent and not more than 110.0 percent of the labeled amount. Cyanocobalamin Co 57 Oral Solution contains a suitable antimicrobial agent.
Specific activity: not less than 0.02 MBq (0.5 µCi) per µg of cyanocobalamin.
Packaging and storage Preserve in tight containers, protected from light, and store in a cold place.
Labeling Label it to include the following: the date of calibration; the amount of 57Co as cyanocobalamin expressed as total megabecquerels (microcuries) and as megabecquerels (microcuries) per mL at the time of calibration; the amount of cyanocobalamin expressed in µg per mL; the name and quantity of the added preservative; the expiration date; and the statement CautionRadioactive 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 57Co is 270.9 days, and directs that the Oral Solution be protected from light.
USP Reference standards 11
Radionuclide identification (see Radioactivity 821) Its gamma-ray spectrum is identical to that of a specimen of 57Co of known purity that exhibits a major photopeak having an energy of 0.122 MeV.
Uniformity of dosage units 905
for oral solution packaged in single-unit containers:meets the requirements.
Deliverable volume 698
for oral solution packaged in multiple-unit containers: meets the requirements.
pH 791: between 4.0 and 5.5.
Mobile phase Prepare a solution of 10.0 g of dibasic sodium phosphate in 1000 mL of water, and adjust with phosphoric acid to a pH of 3.5. Prepare a mixture of this solution and methanol (73.5:26.5), mix, and degas. Use within 2 days.
Test solution Use the Oral Solution.
Standard solution Transfer about 10 mg of cyanocobalamin, accurately weighed, to a 100-mL volumetric flask, dilute with Mobile phase to volume, and mix. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 361-nm detector, a gamma detector adjusted for 57Co and a 4.6-mm × 25-cm stainless steel column that contains 5-µm packing L7. The flow rate is about 1 mL per minute.
Procedure Inject about 100 µL of the Standard solution into the chromatograph, record the chromatogram for 30 minutes, and note the retention time of the cyanocobalamin peak. Inject 100 µL of the Test solution into the chromatograph, and record the chromatogram for three times the retention time of cyanocobalamin. Measure the peak areas using the gamma detector, and calculate the percentage of cyanocobalamin present as cyanocobalamin 57Co in the portion of Oral Solution taken by the formula:
100(rU / rT)in which rU is the peak response for cyanocobalamin 57Co obtained from the Test solution; and rT is the total of all the peak area responses in the radiochromatogram obtained from the Test solution. Not less than 90% of the total radioactivity is found as cyanocobalamin 57Co.
Radionuclidic purity Using a suitable calibrated instrument (see Radioactivity 821) and standardized solutions of 58Co, 57Co, and 60Co, record the gamma spectrum of the Oral Solution. The spectrum does not differ significantly from that of the standardized 57Co solution. Determine the relative amounts of 58Co, 57Co, and 60Co present. Cobalt 58 has a half-life of 70.9 days, and its presence is shown by 0.511-MeV and 0.811-MeV gamma photons. Cobalt 60 has a half-life of 5.27 years, and its presence is shown by 1.173-MeV and 1.333-MeV gamma photons. Not more than 1% of the total radioactivity is due to 60Co; and not more than 2% of the total radioactivity is due to 58Co, 60Co, and other radionuclidic impurities.
Content of cyanocobalamin Determine the content, in µg per mL, of cyanocobalamin as directed under Vitamin B12 Activity Assay 171.
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