Sodium Chromate Cr 51Injection

Chromic acid (H251CrO4),disodium salt.
Disodium chromate (Na251CrO4) [7775-11-3].
»Sodium Chromate Cr 51Injection is a sterile solution of radioactive chromium (51Cr)processed in the form of sodium chromate in Water for Injection.For those uses where an isotonic solution is required,Sodium Chloride may be added in appropriate amounts as provided under Injections á1ñ.Chromium 51is produced by the neutron bombardment of enriched chromium 50.
Sodium Chromate Cr 51Injection contains not less than 90.0percent and not more than 110.0percent of the labeled amount of 51Cr as sodium chromate expressed in megabecquerels (millicuries)per mLat the time indicated in the labeling.The sodium chromate content is not less than 90.0percent and not more than 110.0percent of the labeled amount.The specific activity is not less than 370megabecquerels (10millicuries)per mg of sodium chromate at the end of the expiry period.Other chemical forms of radioactivity do not exceed 10.0percent of the total radioactivity.
Packaging and storage— Preserve in single-dose or in multiple-dose containers.
Labeling— Label it to include the following,in addition to the information specified for Labelingunder Injections á1ñ:the time and date of calibration;the amount of sodium chromate expressed in µg per mL;the amount of 51Cr as sodium chromate expressed as total megabecquerels (millicuries)and as megabecquerels (millicuries)per mLat the time of calibration;a statement to indicate whether the contents are intended for diagnostic or therapeutic use;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 the quantity of chromium,and also indicates that the radioactive half-life of 51Cr is 27.8days.
Radionuclide identification (see Radioactivity á821ñ)— Its gamma-ray spectrum is identical to that of a specimen of 51Cr of known purity that exhibits a photopeak having an energy of 0.320MeV.
Bacterial endotoxins á85ñ— It contains not more than 175/VUSP Endotoxin Unit per mLof the Injection,when compared with the USP Endotoxin RS,in which Vis the maximum recommended total dose,in mL,at the expiration date or time.
pHá791ñ: between 7.5and 8.5.
Radiochemical purity— Place a volume of Injection,appropriately diluted so that it provides a count rate of about 20,000counts per minute,about 25mm from one end of a 25-×300-mm strip of chromatographic paper (see Chromatography á621ñ),and immediately develop with a mixture of 5parts of water,2parts of dilute alcohol (9.5in 10),and 1part of ammonium hydroxide.Air-dry the chromatogram,and determine the radioactivity distribution by scanning the chromatogram with a suitable collimated radiation detector.The radioactivity of the chromate band is not less than 90.0%of the total radioactivity.The RFvalue for the chromate band falls within ±10%of the value found for a known sodium chromate specimen when determined under identical conditions.
Other requirements— It meets the requirements under Injections á1ñ,except that it is not subject to the recommendation on Volume in Container.
Assay for sodium chromate—
Standard stock preparation— Dissolve 3.735g of potassium chromate in 1000mLof water to obtain a solution having a known concentration of 1.0mg per mLof chromium.
Standard preparation— Pipet 0.25,0.50,0.75,0.100,0.125,and 0.150mLof the Standard stock preparation,accurately measured,into separate 100-mLvolumetric flasks.To each flask add 0.42mLof 0.1Nsodium bicarbonate,and dilute with water to volume to obtain solutions having final concentrations of 0.25,0.50,0.75,1.00,1.25,and 1.50µg of chromium per mL.
Assay preparation— Use the Injection.
Blank preparation— Transfer 0.42mLof 0.1Nsodium bicarbonate to a 100-mLvolumetric flask,and dilute with water to volume.
Procedure— Concomitantly determine the absorbances of the Assay preparation,the Standard preparations,and the Blank preparationat the chromium emission line at 357.7nm with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering á851ñ)equipped with a chromium hollow-cathode lamp and an air–acetylene (fuel-rich)flame using water to set the instrument to zero.Plot the absorbances of the Standard preparationsand the Blank preparationversus concentration,in µg per mL,of chromium,and perform a regression analysis.Asuitable standard curve will have an intercept between –0.002and +0.002,and a regression coefficient of not less than 0.99.Using the standard curve so obtained,determine the concentration,C,in µg per mL,of chromium in the Injection taken.Calculate the quantity of sodium chromate,in µg per mL,by the formula:
3.115C,
in which 3.115is the conversion factor.
Assay for radioactivity— Using a suitable counting assembly (see Selection of a Counting Assemblyunder Radioactivity á821ñ),determine the radioactivity,in MBq (µCi)per mL,of Injection by use of a calibrated system as directed under Radioactivity á821ñ.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 466
Pharmacopeial Forum:Volume No.27(3)Page 2526
Phone Number:1-301-816-8305