pH 
791
:
between 5.0 and 7.5, in a solution containing 60 mg per mL, except where it is labeled as containing sodium citrate it is between 6.0 and 7.5.
Loss on drying 731—
Dry about 100 mg, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60
for 3 hours: it loses not more than 1.5% of its weight.
Assay—
Mobile phase, Standard preparation, Resolution solution, and Chromatographic system—
Proceed as directed in the
Assay under
Penicillin G Sodium.
Assay preparation 1 (where it is represented as being in a single-dose container)—
Constitute Penicillin G Sodium for Injection as directed in the labeling. Withdraw all of the withdrawable contents, using a hypodermic needle and syringe, and quantitatively dilute with water to obtain a solution containing about 160 Penicillin G Units per mL.
Assay preparation 2 (where the label states the quantity of penicillin G in a given volume of constituted solution)—
Constitute Penicillin G Sodium for Injection as directed in the labeling. Quantitatively dilute an accurately measured volume of the constituted solution with water to obtain a solution containing about 160 Penicillin G Units per mL.
Assay preparation 3 (where it contains Sodium Citrate)—
Transfer about 50 mg of the Penicillin G Sodium for Injection, accurately weighed, to a 500-mL volumetric flask, add about 400 mL of water, and shake to dissolve. Dilute with water to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Penicillin G Sodium. Calculate the number of Penicillin G Units in the container or in the portion of constituted solution taken by the formula:
(L/D)(PWS / 50)(rU / rS),
in which
L is the labeled quantity of Penicillin G Units in the container or in the volume of constituted solution taken;
D is the concentration, in Penicillin G Units per mL, of
Assay preparation 1 or
Assay preparation 2, on the basis of the labeled quantity in the container or in the portion of constituted solution taken and the extent of dilution;
P is the specified potency, in Penicillin G Units per mg, of
USP Penicillin G Potassium RS;
WS is the weight, in mg, of
USP Penicillin G Potassium RS taken to prepare the
Standard preparation; and
rU and
rS are the penicillin G peak responses obtained from the
Assay preparation and the
Standard preparation, respectively. Calculate the potency, in Penicillin G Units per mg, of the Penicillin G Sodium for Injection taken by the formula:
10(WS / WU)(P)(rU / rS),
in which
WS and
WU are the weights, in mg, of
USP Penicillin G Potassium RS and Penicillin G Sodium for Injection taken to prepare the
Standard preparation and
Assay preparation 3, respectively; and the other terms are as defined above. Perform the above procedure on 10 containers (where it is represented as being in a single-dose container) and, if necessary, on 10 containers (where the label states the quantity of penicillin G in a given volume of constituted solution). Use the individual results to determine the
Uniformity of dosage units and the average thereof as the
Assay value.
