Penicillin G Potassium
(pen'' i sil' in poe tas' ee um).
4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-[(phenylacetyl)amino-], monopotassium salt, [2S-(2,5,6)]-.
Monopotassium (2S,5R,6R)-3,3-dimethyl-7-oxo-6-(2-phenylacetamido)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate [113-98-4].
» Penicillin G Potassium has a potency of not less than 1440 Penicillin G Units and not more than 1680 Penicillin G Units per mg.
Packaging and storage Preserve in tight containers.
Labeling Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.
USP Reference standards 11
Crystallinity 695: meets the requirements.
pH 791: between 5.0 and 7.5, in a solution containing 60 mg per mL.
Loss on drying 731 Dry about 100 mg, accurately weighed, in a capillary-stoppered bottle in vacuum at 60 for 3 hours: it loses not more than 1.5% of its weight.
Other requirements Where the label states that Penicillin G Potassium is sterile, it meets the requirements for Sterility and Bacterial endotoxins under Penicillin G Potassium for Injection. Where the label states that Penicillin G Potassium must be subjected to further processing during the preparation of injectable dosage forms, it meets the requirements for Bacterial endotoxins under Penicillin G Potassium for Injection.
Mobile phase Prepare a mixture of 0.01 M monobasic potassium phosphate and methanol (60:40). Make adjustments if necessary (see System Suitability under Chromatography 621).
Resolution solution Prepare a solution in water containing about 0.1 mg each of USP Penicillin G Potassium RS and 2-phenylacetamide per mL.
Standard preparation Transfer about 5 mg of USP Penicillin G Potassium RS, accurately weighed, to a 50-mL volumetric flask, add about 45 mL of water, and shake to dissolve. Dilute with water to volume, and mix. This solution contains the equivalent of about 160 Penicillin G Units per mL.
Assay preparation Transfer about 5 mg of Penicillin G Potassium, accurately weighed, to a 50-mL volumetric flask, add about 45 mL of water, and shake to dissolve. Dilute with water to volume, and mix.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a 220-nm detector and a 4.6-mm × 10-cm column that contains 5-µm packing L1. The flow rate is about 1 mL per minute. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.8 for 2-phenylacetamide and 1.0 for penicillin G; and the resolution, R, between 2-phenylacetamide and penicillin G is not less than 2.0. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 1000 theoretical plates; the tailing factor 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 10 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 potency, in Penicillin G Units per mg, of the Penicillin G Potassium taken by the formula:
(PWS / WU)(rU / rS)in which P is the specified potency, in Penicillin G Units per mg, of USP Penicillin G Potassium RS; WS and WU are the weights, in mg, of USP Penicillin G Potassium RS and the Penicillin G Potassium taken to prepare the Standard preparation and the Assay preparation, respectively; and rU and rS are the penicillin G peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 4240