» Digoxin Injection is a sterile solution of Digoxin in Water for Injection and Alcohol or other suitable solvents. It contains not less than 90.0 percent and not more than 105.0 percent of the labeled amount of C41H64O14.
Packaging and storage Preserve in single-dose containers, preferably of Type I glass. Avoid exposure to excessive heat.
USP Reference standards 11
USP Endotoxin RS
A: Injection meets the requirements for Identification test A under Digoxin Oral Solution.
B: Chloramine Ttrichloroacetic acid reagent, Spotting solvent, and Standard solutionProceed as directed for Identification test B under Digoxin Oral Solution.
Test solution Pipet a volume of Injection, equivalent to 0.5 mg of digoxin, into a separator, and add 5 mL of water. Extract with three 10-mL portions of chloroform, combining the extracts in a conical flask. Evaporate the combined chloroform extracts on a steam bath with the aid of a current of air to dryness. (If traces of water or propylene glycol remain, dry the flask in vacuum at 100 for 30 minutes.) Dissolve the residue in 2 mL of Spotting solvent.
Procedure Proceed as directed for Procedure in the test for Related glycosides under Digoxin, except to omit the use of the Gitoxin standard solution. Examine the plate under long-wavelength UV light: the RF value of the principal spot in the chromatogram of the Test solution corresponds to that of the Standard solution.
Bacterial endotoxins 85 It contains not more than 200.0 USP Endotoxin Units per mg of digoxin.
Alcohol content 611: between 9.0% and 11.0% of C2H5OH.
Other requirements It meets the requirements under Injections 1.
Mobile phase Proceed as directed in the Assay under Digoxin.
Standard preparation Dissolve an accurately weighed quantity of USP Digoxin RS in diluted alcohol, and dilute quantitatively with diluted alcohol to obtain a solution having a known concentration of about 250 µg per mL. Use a sonic bath to aid dissolution. If necessary, dilute quantitatively to match, approximately, the concentration of the Injection.
Chromatographic system and System suitability preparation Proceed as directed in the Assay under Digoxin.
Procedure Separately inject equal volumes (about 10 µL) of the Standard preparation and Injection into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in µg, of C41H64O14 in each mL of the Injection taken by the formula:
C(rU / rS)in which C is the concentration, in µg per mL, of USP Digoxin RS in the Standard preparation; and rU and rS are the responses for the digoxin peaks obtained from the Injection and the Standard preparation, respectively.
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USP35NF30 Page 2905Pharmacopeial Forum: Volume No. 28(2) Page 279