Ampicillin Sodium
C16H18N3NaO4S 371.39

4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, [6-(aminophenylacetyl)amino]-3,3-dimethyl-7-oxo-, monosodium salt, [2S-[2,5,6(S*)]]-.

Monosodium d-()-6-(2-amino-2-phenylacetamido)-3,3dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate [69-52-3].
» Ampicillin Sodium has a potency equivalent to not less than 845 µg and not more than 988 µg of ampicillin (C16H19N3O4S) per mg, calculated on the anhydrous basis.
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.
Identification—
B: It responds to the tests for Sodium 191.
Crystallinity 695: meets the requirements. [note—Ampicillin Sodium in the freeze-dried form is exempt from this requirement.]
pH 791: between 8.0 and 10.0, in a solution containing 10.0 mg of ampicillin per mL.
Water, Method I 921: not more than 2.0%.
Dimethylaniline 223: meets the requirement, the Internal standard solution, Standard preparation, and Test preparation being prepared as follows.
Internal standard solution— Dissolve 75 mg of N,N-diethylaniline in 25 mL of 1 N hydrochloric acid, and dilute quantitatively and stepwise with water to obtain a solution containing about 30 µg per mL.
Standard preparation— Transfer 50.0 mg of N,N-dimethylaniline to a 50-mL volumetric flask, add 25 mL of 1 N hydrochloric acid, swirl to dissolve, dilute with water to volume, and mix. Transfer 2.0 mL of the resulting solution to a 100-mL volumetric flask, dilute with water to volume, and mix. To a suitable centrifuge tube add 1.0 mL of this solution, 1.0 mL of 1.25 N sodium hydroxide, 1.0 mL of Internal standard solution, and 1.0 mL of cyclohexane, shake vigorously for 1 minute, and centrifuge. Use the clear supernatant as the Standard preparation.
Test preparation— Transfer 1.0 g of Ampicillin Sodium to a suitable centrifuge tube, add 2 mL of 1.25 N sodium hydroxide, swirl to dissolve the specimen, add 1.0 mL of Internal standard solution and 1.0 mL of cyclohexane, shake vigorously for 1 minute, and centrifuge. Use the clear supernatant as the Test preparation.
Limit of methylene chloride—
Internal standard solution— Prepare a solution of dioxane in dimethyl sulfoxide containing about 2.1 mg per mL.
Standard solution— Dissolve an accurately weighed quantity of methylene chloride in Internal standard solution to obtain a solution having a known concentration of about 0.33 mg per mL.
Test solution— Dissolve about 500 mg of Ampicillin Sodium, accurately weighed, in 3.0 mL of Internal standard solution.
Chromatographic system (see Chromatography 621)— The gas chromatograph is equipped with a flame-ionization detector and a 1.8-m × 4-mm glass column packed with a 10% phase G39 on unsilanized support S1A. The column temperature is maintained at 65, and the injection port and the detector block temperatures are maintained at about 100 and 260, respectively. Nitrogen is used as the carrier gas at a flow rate of about 60 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative retention times are about 0.5 for methylene chloride and 1.0 for dioxane; the resolution, R, between the methylene chloride peak and the dioxane peak is not less than 4; and the relative standard deviation for replicate injections is not more than 5%.
Procedure— Separately inject equal volumes (about 1 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the methylene chloride and dioxane peaks. Calculate the percentage of methylene chloride in the portion of Ampicillin Sodium taken by the formula:
(300C / m)(RU / RS)
in which C is the concentration, in mg per mL, of methylene chloride in the Standard solution; m is the quantity, in mg, of Ampicillin Sodium taken to prepare the Test solution; and RU and RS are the ratios of the response of the methylene chloride peak to that of the dioxane peak obtained from the Test solution and the Standard solution, respectively. The limit is 0.2%.
Other requirements— Where the label states that Ampicillin Sodium is sterile, it meets the requirements for Sterility and Bacterial endotoxins under Ampicillin for Injection. Where the label states that Ampicillin Sodium must be subjected to further processing during the processing of injectable dosage forms, it meets the requirements for Bacterial endotoxins under Ampicillin for Injection.
Assay—
Mobile phase, Diluent, Standard preparation, Resolution solution, and Chromatographic system Prepare as directed in the Assay under Ampicillin.
Assay preparation— [note—Ampicillin Sodium is hygroscopic. Minimize exposure to the atmosphere, and weigh promptly.] Transfer an accurately weighed quantity of Ampicillin Sodium, equivalent to about 100 mg of anhydrous ampicillin, to a 100-mL volumetric flask, dissolve in and dilute with Diluent to volume, and mix. Use this solution promptly after preparation.
Procedure— Proceed as directed for Procedure in the Assay under Ampicillin. Calculate the quantity, in µg, of ampicillin (C16H19N3O4S) in each mg of Ampicillin Sodium taken by the formula:
100(CP / W)(rU / rS)
in which W is the weight, in mg, of Ampicillin Sodium taken to prepare the Assay preparation; and the other terms are as defined in the Assay under Ampicillin.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
Scientist
1-301-816-8161
(MDANT05) Monograph Development-Antibiotics
Reference Standards Lili Wang, Technical Services Scientist
1-301-816-8129
RSTech@usp.org
USP32–NF27 Page 1553
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.