Ampicillin Capsules
»Ampicillin Capsules contain an amount of ampicillin (anhydrous or as the trihydrate)equivalent to not less than 90.0percent and not more than 120.0percent of the labeled amount of ampicillin (C16H19N3O4S).
Packaging and storage— Preserve in tight containers.
Labeling— Label the Capsules to indicate whether the ampicillin therein is in the anhydrous form or is the trihydrate.
Identification— Prepare a solution containing about 5mg of ampicillin per mL,using powder from Ampicillin Capsules,in a mixture of acetone and 0.1Nhydrochloric acid (4:1).Prepare a Standard solution of USP Ampicillin RSto contain 5mg per mLin the same solvent mixture.Apply separately 2µLof each solution on a thin-layer chromatographic plate (see Chromatography á621ñ)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 acetone,water,toluene,and glacial acetic acid (650:100:100:25).When 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.Locate the spots on the plate by spraying lightly with a solution of ninhydrin in alcohol containing 3mg per mL,and dry at 90for 15minutes:the RFvalue of the principal spot obtained from the solution under test corresponds to that obtained from the Standard solution.
Dissolution,Procedure for a Pooled Sample á711ñ—
Medium: water;900mL.
Apparatus 1: 100rpm.
Time: 45minutes.
Standard preparation— Dissolve an accurately weighed quantity of USP Ampicillin RSin water to obtain a solution having a known concentration of about L/900mg per mL,Lbeing the labeled amount,in mg,of ampicillin per Capsule.
Procedure— Proceed as directed for Procedurein the section Antibiotics—Hydroxylamine Assayunder Automated Methods of Analysis á16ñ,using a filtered portion of the solution under test as the Assay preparation.Calculate the quantity,in mg,of C16H19N3O4Sdissolved by the formula:
0.9CP(AU/AS).
Tolerances— Not less than 75%(Q)of the labeled amount of C16H19N3O4Sis dissolved in 45minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Water,Method Iá921ñ: not more than 4.0%where the Capsules contain anhydrous Ampicillin,or between 10.0%and 15.0%where the Capsules contain Ampicillin trihydrate.
Assay—
Standard preparation— Prepare as directed for Standard Preparationunder Iodometric Assay—Antibiotics á425ñ,using USP Ampicillin RS.
Assay preparation— Place not fewer than 5Capsules in a high-speed glass blender jar containing an accurately measured volume of water,and blend for 4±1minutes.Dilute an accurately measured volume of this stock solution quantitatively and stepwise with water to obtain an Assay preparationcontaining about 1.25mg of ampicillin per mL.
Procedure— Proceed as directed for Procedureunder Iodometric Assay—Antibiotics á425ñ.Calculate the quantity,in mg,of ampicillin (C16H19N3O4S)in each Capsule taken by the formula:
(T/D)(F/2000)(B-I),
in which Tis the labeled quantity,in mg,of ampicillin in each Capsule;and Dis the concentration,in mg per mL,of ampicillin in the Assay preparationon the basis of the labeled quantity in each Capsule and the extent of dilution.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 152
Pharmacopeial Forum:Volume No.30(1)Page 55
Phone Number:1-301-816-8335