Packaging and storage—
Preserve in single-dose glass or plastic containers. Glass containers are preferably of Type I or Type II glass.
Labeling—
The label states the content of each electrolyte in terms of milliequivalents in a given volume. The label states the total osmolar concentration in mOsmol per L. When the contents are less than 100 mL, the label alternatively may state the total osmolar concentration in mOsmol per mL.
Identification—
B:
The retention time of the acetate peak in the chromatogram of the Assay preparation corresponds to that of the Standard preparation, obtained as directed in the Assay for acetate.
C:
Where gluconate is purported to be present, the retention time of the gluconate peak in the chromatogram of the Assay preparation corresponds to that of the Standard preparation, obtained as directed in the Assay for gluconate.
D:
Where phosphate is purported to be present, add 5 mL of the Injection and 1 mL of
ammonium molybdate TS to a test tube, and mix: a yellow precipitate, which is soluble in 6 N ammonium hydroxide, is formed.
Other requirements—
It meets the requirements under
Injections
1
.
Assay for potassium and sodium—
Internal standard solution, Potassium stock solution, Sodium stock solution, Stock standard preparation, and Standard preparation—
Prepare as directed in the
Assay for potassium and sodium under
Potassium Chloride in Sodium Chloride Injection.
Assay preparation—
Transfer 5.0 mL of Injection to a 500-mL volumetric flask, dilute with Internal standard solution to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay for potassium and sodium under
Potassium Chloride in Sodium Chloride Injection. Calculate the quantity, in mg, of potassium (K) in each mL of the Injection taken by the formula:
C(RU,766 / RU,671)(RS,671 / RS,766),
in which the terms are as defined therein. Each mg of potassium is equivalent to 0.02558 mEq of potassium. Calculate the quantity, in mg, of sodium (Na) in each mL of the Injection taken by the formula:
C(RU,589 / RU,671)(RS,671 / RS,589),
in which the terms are as defined therein. Each mg of sodium is equivalent to 0.04350 mEq of sodium.
Assay for magnesium—
[NOTE—Concentrations of the
Standard preparations and the
Assay preparation may be modified to fit the linear or working range of the atomic absorption spectrophotometer.
]
Lanthanum chloride solution—
Transfer 17.69 g of lanthanum chloride to a 200-mL volumetric flask, add 100 mL of water, and carefully add 50 mL of hydrochloric acid. Mix, and allow to cool. Dilute with water to volume, and mix.
Dilute hydrochloric acid—
Prepare by mixing 678 mL of hydrochloric acid with sufficient water to make 3000 mL.
Blank solution—
Transfer 5.0 mL of Lanthanum chloride solution to a 100-mL volumetric flask, dilute with Dilute hydrochloric acid to volume, and mix.
Magnesium stock solution—
Transfer 1.00 g of magnesium metal to a 1000-mL volumetric flask containing 10 mL of water. Slowly add 10 mL of hydrochloric acid, and swirl to dissolve the metal. Dilute with Dilute hydrochloric acid to volume, and mix. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, dilute with Dilute hydrochloric acid to volume, and mix. This solution contains 100 µg of magnesium (Mg) per mL.
Standard preparations—
To three separate 100-mL volumetric flasks, each containing 5.0 mL of Lanthanum chloride solution, add 10.0, 15.0, and 20 mL, respectively, of Magnesium stock solution. Dilute the contents of each flask with Dilute hydrochloric acid to volume, and mix. These three solutions contain 10.0, 15.0, and 20.0 µg, respectively, of magnesium (Mg) per mL.
Assay preparation—
Transfer an accurately measured volume of Injection, equivalent to about 20 mg (1.65 mEq) of magnesium, to a 1000-mL volumetric flask containing 50.0 mL of Lanthanum chloride solution. Dilute the contents of the flask with Dilute hydrochloric acid to volume, and mix.
Procedure—
Concomitantly determine the absorbances of the
Standard preparations and the
Assay preparation at the magnesium emission line at 285.2 nm, with an atomic absorption spectrophotometer (see
Spectrophotometry and Light-scattering
851
) equipped with a magnesium hollow-cathode lamp and an air–acetylene flame, using the
Blank solution as the blank. Plot the absorbances of the
Standard preparations versus concentration, in µg per mL, of magnesium, 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 magnesium in the
Assay preparation. Calculate the quantity, in µg, of magnesium (Mg) in each mL of the Injection taken by the formula:
1000(C/V),
in which
V is the volume, in mL, of Injection taken to prepare the
Assay preparation.
Assay for chloride—
Transfer an accurately measured volume of Injection, equivalent to about 55 mg of chloride (1.55 mEq), to a suitable conical flask, and add water, if necessary, to bring the volume to about 10 mL. Add 10 mL of glacial acetic acid, 75 mL of methanol, and 0.5 mL of
eosin Y TS. Titrate, with shaking, with 0.1 N silver nitrate VS to a pink endpoint. Each mL of 0.1 N silver nitrate is equivalent to 3.545 mg (0.1 mEq) of Cl.
Assay for acetate—
Mobile phase—
Prepare a filtered and degassed solution of 0.05 N sulfuric acid. Make adjustments if necessary (see
System Suitability under
Chromatography
621
).
Standard preparation—
Dissolve an accurately weighed quantity of sodium acetate trihydrate in water to obtain a Standard preparation having a known concentration of about 1.2 mg of sodium acetate trihydrate (about 0.0088 mEq of acetate) per mL.
Assay preparation—
Quantitatively dilute an accurately measured volume of Injection with water to obtain a solution containing about 0.0088 mEq of acetate per mL.
Chromatographic system (see Chromatography
621
)—
The liquid chromatograph is equipped with a 210-nm detector, a 4.6-mm × 3-cm guard column containing packing L17, and a 7.8-mm × 30-cm analytical column containing packing L17. The column temperature is maintained at about 60

. The flow rate is about 0.8 mL per minute. Chromatograph the
Standard preparation, and record the responses as directed for
Procedure: the tailing factor for the analyte peak is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mEq per L, of acetate (C
2H
3O
2) in the Injection taken by the formula:
(C/136.08)(L/D)(rU / rS),
in which
C is the concentration, in mg per mL, of sodium acetate trihydrate in the
Standard preparation; 136.08 is the molecular weight of sodium acetate trihydrate;
L is the labeled quantity, in mEq per L, of acetate in the Injection;
D is the quantity, in mEq per mL, of acetate in the
Assay preparation, based on the labeled quantity and the extent of dilution; and
rU and
rS are the acetate peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
Assay for gluconate (if present)—
Mobile phase—
Prepare a filtered and degassed solution of 0.05 N sulfuric acid. Make adjustments if necessary (see
System Suitability under
Chromatography
621
).
Assay preparation—
Dilute an accurately measured volume of Injection quantitatively with water to obtain a solution containing about 0.004 mEq of gluconate per mL.
Chromatographic system (see Chromatography
621
)—
The liquid chromatograph is equipped with a 210-nm detector, a 4.6-mm × 3-cm guard column containing packing L17, and a 7.8-mm × 30-cm analytical column containing packing L17. The flow rate is about 0.8 mL per minute. Chromatograph the
Standard preparation, and record the responses as directed for
Procedure: the tailing factor for the analyte peak is not more than 2.0, and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mEq per L, of gluconate (C
6H
11O
7) in the Injection taken by the formula:
(C/234.25)(L/D)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Potassium Gluconate RS in the
Standard preparation; 234.25 is the molecular weight of anhydrous potassium gluconate;
L is the labeled quantity, in mEq per L, of gluconate in the Injection;
D is the quantity, in mEq per mL, of gluconate in the
Assay preparation, based on the labeled quantity and the extent of dilution; and
rU and
rS are the gluconate peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
Assay for phosphate (if present)—
Ammonium molybdate solution—
Transfer 25 g of ammonium molybdate to a 500-mL volumetric flask, add about 300 mL of water, and swirl to dissolve solution. Add 75 mL of sulfuric acid, and swirl. Allow to cool, dilute with water to volume, and mix.
Hydroquinone solution—
Dissolve 0.5 g of hydroquinone in 100 mL of water, add 1 drop of sulfuric acid, and mix. [NOTE—Prepare this solution fresh daily.]
Sodium sulfite solution—
Dissolve 1 g of sodium sulfite in water to make 5 mL of solution. [NOTE—Prepare this solution fresh daily.]
Standard preparation—
Dissolve an accurately weighed quantity of monobasic potassium phosphate in water to obtain a solution having a known concentration of about 0.11 mg per mL.
Assay preparation—
Transfer an accurately measured volume of Injection, equivalent to about 4 mg (0.126 mEq) of phosphate, to a 50-mL volumetric flask, dilute with water to volume, and mix.
Blank—
Use water.
Procedure—
Transfer 2.0 mL each of the
Standard preparation, the
Assay preparation, and the
Blank to separate test tubes. To each test tube add 1.0 mL of
Ammonium molybdate solution, mix, and allow to stand for 3 minutes. Add 1.0 mL of
Hydroquinone solution, and mix. Add 1.0 mL of
Sodium sulfite solution, mix, and allow to stand for 30 minutes. Concomitantly determine the absorbances of the
Assay preparation and the
Standard preparation at 640 nm, using water to zero the instrument. Calculate the quantity, in mg, of phosphate (PO
4) in each mL of the Injection taken by the formula:
50(94.97/136.09)(C/V)(AU / AS),
in which 94.97 is the formula weight of phosphate (PO
4); 136.09 is the molecular weight of monobasic potassium phosphate;
C is the concentration, in mg per mL, of monobasic potassium phosphate in the
Standard preparation; V is the volume, in mL, of Injection taken; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively, corrected for any absorbance of the solution from the
Blank.