Citric Acid, Magnesium Oxide, and Sodium Carbonate Irrigation
» Citric Acid, Magnesium Oxide, and Sodium Carbonate Irrigation is a sterile solution of Citric Acid, Magnesium Oxide, and Sodium Carbonate in Water for Injection. It contains not less than 95.0 percent and not more than 105.0 percent of the labeled amounts of citric acid (C6H8O7·H2O), magnesium oxide (MgO), and sodium carbonate (Na2CO3).
Packaging and storage Preserve in single-dose containers, preferably of Type I or Type II glass.
USP Reference standards 11
USP Endotoxin RS
B: To 10 mL of the Irrigation add 1 mL of mercuric sulfate TS, heat to boiling, and add a few drops of potassium permanganate TS: a white precipitate is formed.
Bacterial endotoxins 85 It contains not more than 2.80 Endotoxin Units per mL.
pH 791: between 3.8 and 4.2.
Other requirements It meets the requirements under Injections 1, except that the container may be designed to empty rapidly, and may exceed 1000 mL in capacity.
Assay for citric acid
Mobile Phase, Standard Preparation 1, and Chromatographic System Proceed as directed under Assay for Citric Acid/Citrate and Phosphate 345.
Assay preparation Transfer an accurately measured volume of Irrigation, equivalent to about 130 mg of monohydrate citric acid into a suitable volumetric flask, and proceed as directed for Assay Preparation for Citric Acid/Citrate Assay under Assay for Citric Acid/Citrate and Phosphate 345.
Procedure Proceed as directed for Procedure under 345, and calculate the quantity, in mg per mL, of monohydrate citric acid (C6H8O7·H2O) in the Irrigation taken by the formula:
0.001(210.14 / 189.10)CS(D/V)(rU / rS)in which 210.14 is the molecular weight of citric acid monohydrate; 189.10 is the molecular weight of citrate (C6H5O7); CS is the concentration, in µg per mL, of citrate in Standard Preparation 1; D is the dilution factor; V is the volume, in mL, of Irrigation used to prepare the Assay preparation; and rU and rS are the citrate peak areas obtained from the Assay preparation and Standard Preparation 1, respectively.
Assay for magnesium oxide Transfer an accurately measured volume of Irrigation, equivalent to about 40 mg of magnesium oxide, to a beaker containing 130 mL of water heated to 75 ± 5, and add 4 mL of ammonium chloride TS and then 5 mL of ammonium hydroxide. Mix, and add slowly, with stirring, 8 mL of 8-hydroxyquinoline TS. After allowing to stand for 30 minutes at 75, filter through a sintered-glass crucible, previously dried and weighed, and wash the precipitate with 50 mL of a warm mixture of water and 6 N ammonium hydroxide (45:5), followed by 50 mL of cool water. Dry the crucible and contents at 105 for 3 hours, cool, and weigh. Determine the equivalent of MgO in the portion of Irrigation taken by multiplying the weight of C18H12MgN2O2·2H2O so obtained by 0.1156.
Assay for sodium carbonate
Sodium chloride stock solution Transfer 475 mg of sodium chloride, previously dried at 105 for 2 hours and accurately weighed, to a 100-mL volumetric flask. Dissolve in water, dilute with water to volume, and mix.
Internal standard solution Transfer 636 mg of lithium chloride to a 1000-mL volumetric flask, dissolve in and dilute with water to volume, and mix.
Standard preparation Quantitatively prepare a mixture of Internal standard solution and Sodium chloride stock solution (99:1).
Assay preparation Dilute an accurately measured volume of Irrigation quantitatively with water to obtain a stock solution containing about 4.4 mg of sodium carbonate per mL. Quantitatively prepare a mixture of Internal standard solution and this stock solution (99:1).
Procedure Concomitantly determine the emittances of the Standard preparation and the Assay preparation at 591 nm and 671 nm with a suitable flame photometer, adjusting the instrument to zero emittance with Internal standard solution. Calculate the quantity, in mg, of Na2CO3 in each mL of the Irrigation taken by the formula:
(105.99/116.88)(C)(L/D)(RU,591 / RU,671)(RS,671 / RS,591)in which 105.99 is the molecular weight of sodium carbonate; 116.88 is two times the molecular weight of sodium chloride; C is the concentration, in mg per mL, of sodium chloride in the Sodium chloride stock solution; L is the labeled quantity, in mg per mL, of sodium carbonate in the Irrigation; D is the concentration, in mg per mL, of sodium carbonate in the stock solution used to prepare the Assay preparation, on the basis of the labeled quantity in each mL, and the extent of dilution; RU,591 and RU,671 are the emittance readings obtained from the Assay preparation at the wavelengths indicated by the subscripts; and RS,671 and RS,591 are the emittance readings obtained from the Standard preparation at the wavelengths indicated by the subscripts.
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USP35NF30 Page 2689Pharmacopeial Forum: Volume No. 31(2) Page 394