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Penicillin G Procaine
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C16H18N2O4S·C13H20N2O2·H2O 588.72

4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-[(phenylacetyl)amino-], 2S-(2,5,6)-, compd. with 2-(diethylamino)ethyl 4-aminobenzoate (1:1) monohydrate.

(2S,5R,6R)-3,3-Dimethyl-7-oxo-6-(2-phenylacetamido)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid compound with 2-(diethylamino)ethyl p-aminobenzoate (1:1) monohydrate [6130-64-9].

Anhydrous 570.71 [54-35-3].
» Penicillin G Procaine has a potency of not less than 900 Penicillin G Units and not more than 1050 Penicillin G Units per mg.
Packaging and storage— Preserve in Containers for Sterile Solids as described under Injections 1.
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.
Identification— Prepare a solution of it containing about 12,000 Penicillin G Units per mL in a solvent mixture consisting of acetone, 0.1 M citric acid, and 0.1 M sodium citrate (2:1:1). Prepare a Standard solution of USP Penicillin G Potassium RS containing about 12,000 Penicillin G Units per mL in the same solvent mixture (Standard solution A). Prepare a Standard solution of USP Procaine Hydrochloride RS containing about 5 mg per mL in the same solvent system (Standard solution B). Apply separately 20 µL of each solution to a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Place the plate in a suitable chromatographic chamber, and develop the chromatogram in a solvent system consisting of a mixture of toluene, dioxane, and glacial acetic acid (90:25:4) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, mark the solvent front, and allow to air-dry. Examine the plate under short- and long-wavelength UV light, noting the positions of the spots. Spray the plate with starch TS followed by dilute iodine TS (1 in 10). Penicillin G appears as a white spot on a purple background: the RF value of the penicillin G spot obtained from the test solution corresponds to that obtained from Standard solution A. Spray the location of the spots visualized with UV light with a 1 in 20 solution of p-dimethylaminobenzaldehyde in methanol. Procaine appears as a bright yellow spot: the RF value of the procaine spot obtained from the test solution corresponds to that obtained from Standard solution B.
Crystallinity 695: meets the requirements.
Bacterial endotoxins 85— Where the label states that Penicillin G Procaine is sterile or that it must be subjected to further processing during the preparation of injectable dosage forms it contains not more than 0.01 USP Endotoxin Unit per 100 Penicillin G Units.
Sterility 71— Where the label states that Penicillin G Procaine is sterile it meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined, except to use Fluid A to which has been added sufficient sterile penicillinase to inactivate the penicillin G and to swirl the vessel until solution is complete before filtering.
pH 791: between 5.0 and 7.5, in a (saturated) solution containing about 300 mg per mL.
Water, Method I 921: between 2.8% and 4.2%.
Content of Penicillin G and procaine—
Mobile phase— Dissolve 14 g of monobasic potassium phosphate and 6.5 g of tetrabutylammonium hydroxide solution (4 in 10) in about 700 mL of water, adjust with 1 N potassium hydroxide to a pH of 7.0, dilute with water to 1000 mL, and mix. Mix 500 mL of this solution, 250 mL of acetonitrile, and 250 mL of water. Adjust with 1 N potassium hydroxide or dilute phosphoric acid (1 in 10) to a pH of 7.5 ± 0.05, filter through a membrane filter of 5 µm or finer porosity, and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation— Using accurately weighed quantities of USP Penicillin G Potassium RS and USP Procaine Hydrochloride RS, prepare a solution in Mobile phase having known concentrations of about 0.8 mg per mL and 0.54 mg per mL, respectively.
Test preparation— Transfer about 70 mg of Penicillin G Procaine, accurately weighed, to a 50-mL volumetric flask, add about 30 mL of Mobile phase, sonicate to dissolve, dilute with Mobile phase to volume, and mix.
Resolution solution— Prepare a solution of penicillin V potassium in Mobile phase containing 2.4 mg per mL. Mix 1 volume of this solution and 3 volumes of Standard preparation.
Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 235-nm detector and a 4-mm × 30-cm column that contains 10-µm packing L1. The flow rate is about 1 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 3.0%. Chromatograph about 10 µL of the Resolution solution, and record the peak responses as directed for Procedure: the resolution, R, between penicillin G and penicillin V is not less than 2.0.
Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Test preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. The relative retention times are 1.0 for procaine and about 2.2 for penicillin G. Calculate the percentage of penicillin G (C16H18N2O4S) in the specimen under test by the formula:
50C(GS / WU)(rU / rS),
in which C is the concentration, in mg per mL, of USP Penicillin G Potassium RS in the Standard preparation, GS is the designated penicillin G content, in percentage, of USP Penicillin G Potassium RS, WU is the amount, in mg, of Penicillin G Procaine taken, and rU and rS are the responses of the penicillin G peaks obtained from the Test preparation and the Standard preparation, respectively: between 51.0% and 59.6% of C16H18N2O4S is found. Calculate the percentage of procaine (C13H20N2O2) in the specimen under test by the formula:
(236.32 / 272.78)(5000C / WU)(rU / rS),
in which 236.32 and 272.78 are the molecular weights of procaine and procaine hydrochloride, respectively, C is the concentration, in mg per mL, of USP Procaine Hydrochloride RS in the Standard preparation, WU is the amount, in mg, of Penicillin G Procaine taken, and rU and rS are the responses of the procaine peaks obtained from the Test preparation and the Standard preparation, respectively: between 37.5% and 43.0% is found.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay—
Standard preparation— Using USP Penicillin G Potassium RS, prepare as directed for Standard preparation under Iodometric Assay—Antibiotics 425.
Assay preparation— Prepare as directed for Assay Preparation under Iodometric Assay—Antibiotics 425, except to dissolve about 100 mg of Penicillin G Procaine, accurately weighed, in 2.0 mL of methanol, and to dilute quantitatively with Buffer No. 1 to obtain a solution containing about 2000 Penicillin G Units per mL.
Procedure— Proceed as directed for Procedure under Iodometric Assay—Antibiotics 425. Calculate the potency, in Penicillin G Units per mg, of the Penicillin G Procaine taken by the formula:
F(B I) / (2D),
in which D is the concentration, in mg per mL, of the Assay preparation, on the basis of the weight of Penicillin G Procaine taken and the extent of dilution, and the other terms are as defined therein.
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 1660
Phone Number : 1-301-816-8223