Selenious Acid Injection
» Selenious Acid Injection is a sterile solution in Water for Injection of Selenious Acid or of selenium dissolved in nitric acid. It contains not less than 95.0 percent and not more than 105.0 percent of the labeled amount of selenium (Se).
Packaging and storage Preserve in single-dose or in multiple-dose containers, preferably of Type I or Type II glass.
Labeling Label the Injection to indicate that it is to be diluted to the appropriate strength with Sterile Water for Injection or other suitable fluid prior to administration.
Identification The Assay preparation, prepared as directed in the Assay, exhibits an absorption maximum at about 196 nm when tested as directed for Procedure in the Assay.
Bacterial endotoxins 85 It contains not more than 3.5 USP Endotoxin Units per µg of selenium.
pH 791: between 1.8 and 2.4.
Particulate matter 788: meets the requirements under small-volume injections.
Other requirements It meets the requirements under Injections 1.
Selenium stock solution Dissolve about 1 g of metallic selenium, accurately weighed, in a minimum volume of nitric acid. [CautionSelenium is toxic; handle it with care.] Evaporate to dryness, add 2 mL of water, and evaporate to dryness. Repeat the addition of water and the evaporation to dryness three times. Dissolve the residue in 3 N hydrochloric acid, transfer to a 1000-mL volumetric flask, dilute with 3 N hydrochloric acid to volume, and mix. This solution contains about 1000 µg of selenium per mL.
Standard preparations Transfer 3.0, 4.0, and 5.0 mL, respectively, of Selenium stock solution to separate 100-mL volumetric flasks, dilute the contents of each flask with water to volume, and mix. These Standard preparations contain, respectively, about 30, 40, and 50 µg of selenium per mL.
Assay preparation Using water as the diluent, quantitatively dilute an accurately measured volume of Injection to obtain a solution containing about 40 µg of selenium per mL.
Procedure Concomitantly determine the absorbances of the Standard preparations and the Assay preparation at the selenium emission line of 196 nm, with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering 851) equipped with a selenium electrodeless discharge lamp and an airacetylene flame, using water as the blank. Plot the absorbances of the Standard preparations versus concentration, in µg per mL, of selenium, and draw the straight line best fitting the three plotted points. From the graph so obtained, determine the concentration C, in µg per mL, of selenium in the Assay preparation. Calculate the quantity, in mg, of selenium in each mL of the Injection taken by the formula:
LC / Din which L is the labeled quantity, in mg per mL, of selenium in the Injection taken, and D is the concentration, in µg of selenium per mL, of the Assay preparation on the basis of the labeled quantity in the Injection and the extent of dilution.
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USP32NF27 Page 3548