Ampicillin
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4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,[6-(aminophenylacetyl)amino]-3,3-dimethyl-7-oxo-,[2S-[2a,5a,6b(S*)]]-.
(2S,5R,6R)-6-[(R)-2-Amino-2-phenylacetamido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid. [69-53-4].
Trihydrate 403.46 [7177-48-2].
»Ampicillin is anhydrous or contains three molecules of water of hydration.It contains not less than 900µg and not more than 1050µg of C16H19N3O4Sper mg,calculated on the dried basis.
Packaging and storage—
Preserve in tight containers.
Labeling—
Label it to indicate whether it is anhydrous or is the trihydrate.Where the quantity of ampicillin is indicated in the labeling of any preparation containing Ampicillin,this shall be understood to be in terms of anhydrous ampicillin (C16H19N3O4S).Where it is intended for use in preparing injectable dosage forms,the label states that it is the trihydrate and that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.
Identification,Infrared Absorption á197Kñ
,except that where the specimen under test is the trihydrate,both it and the USP Ampicillin Trihydrate RSare undried.
Crystallinity á695ñ:
meets the requirements.
Bacterial endotoxins á85ñ—
Where the label states that Ampicillin is sterile or must be subjected to further processing during the preparation of injectable dosage forms,it contains not more than 0.15USP Endotoxin Unit per mg of ampicillin.
Sterility á71ñ—
Where the label states that Ampicillin 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 dissolve 6g in 800mLof Fluid Dcontaining sufficient sterile penicillinase to inactivate the ampicillin and to swirl the vessel until solution is complete before filtering.
pHá791ñ:
between 3.5and 6.0,in a solution containing 10mg per mL.
Water,Method Iá921ñ:
not more than 2.0%where it is labeled as Ampicillin (anhydrous);between 12.0%and 15.0%where it is labeled as Ampicillin (trihydrate).
Dimethylaniline á223ñ:
meets the requirement.
Assay—
Mobile phase—
Prepare a suitable filtered and degassed mixture of water,acetonitrile,1Mmonobasic potassium phosphate,and 1Nacetic acid (909:80:10:1).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Diluent—
Mix 10mLof 1Mmonobasic potassium phosphate and 1mLof 1Nacetic acid,dilute with water to 1000mL,and mix.
Standard preparation—
Dissolve a suitable quantity of USP Ampicillin RS,accurately weighed,in Diluentto obtain a solution having a known concentration of about 1mg per mL,using shaking and sonication,if necessary,to achieve complete dissolution.Use this solution promptly after preparation.
Assay preparation—
Transfer an accurately weighed quantity of Ampicillin,equivalent to about 100mg of anhydrous ampicillin,to a 100-mLvolumetric flask,add about 75mLof Diluent,shake and sonicate,if necessary,to achieve complete dissolution,dilute with Diluentto volume,and mix.Use this solution promptly after preparation.
Resolution solution—
Dissolve caffeine in Standard preparationto obtain a solution containing about 0.12mg per mL.
Chromatographic system (see Chromatography á621ñ)—
The liquid chromatograph is equipped with a 254-nm detector,a 4-mm ×5-cm pre-column containing 5-to 10-µm packing L1,and a 4-mm ×30-cm analytical column containing 5-to 10-µm packing L1.The flow rate is about 2mLper minute.Chromatograph the Resolution solution,and record the peak responses as directed for Procedure:the resolution,R,between the caffeine and the ampicillin peaks is not less than 2.0.The relative retention times are about 0.5for ampicillin and 1.0for caffeine.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the capacity factor,k¢,is not more than 2.5,the tailing factor is not more than 1.4,and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in µg,of ampicillin (C13H19NO4S)in each mg of the Ampicillin taken by the formula:
100(CP/W)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Ampicillin RSin the Standard preparation;Pis the potency,in µg of ampicillin per mg,of USP Ampicillin RS;Wis the weight,in mg,of Ampicillin taken;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 151
Pharmacopeial Forum:Volume No.28(6)Page 1766
Phone Number:1-301-816-8335