» Ampicillin Capsules contain an amount of ampicillin (anhydrous or as the trihydrate) equivalent to not less than 90.0 percent and not more than 120.0 percent 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.
USP Reference standards 11
Identification Prepare a solution containing about 5 mg of ampicillin per mL, using powder from Ampicillin Capsules, in a mixture of acetone and 0.1 N hydrochloric acid (4:1). Prepare a Standard solution of USP Ampicillin RS to contain 5 mg per mL in the same solvent mixture. Apply separately 2 µL of each solution on 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 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 3 mg per mL, and dry at 90 for 15 minutes: the RF value of the principal spot obtained from the solution under test corresponds to that obtained from the Standard solution.
Dissolution, Procedure for a Pooled Sample 711
Medium: water; 900 mL.
Apparatus 1: 100 rpm.
Time: 45 minutes.
Standard preparation Dissolve an accurately weighed quantity of USP Ampicillin RS in water to obtain a solution having a known concentration of about L/900 mg per mL, L being the labeled amount, in mg, of ampicillin per Capsule.
Procedure Proceed as directed for Procedure in the section AntibioticsHydroxylamine Assay under Automated Methods of Analysis 16, using a filtered portion of the solution under test as the Assay preparation. Calculate the quantity, in mg, of C16H19N3O4S dissolved by the formula:
0.9CP(AU / AS).
Tolerances Not less than 75% (Q) of the labeled amount of C16H19N3O4S is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Water, Method I 921: not more than 4.0% where the Capsules contain anhydrous Ampicillin, or between 10.0% and 15.0% where the Capsules contain Ampicillin trihydrate.
Standard preparation Prepare as directed for Standard Preparation under Iodometric AssayAntibiotics 425, using USP Ampicillin RS.
Assay preparation Place not fewer than 5 Capsules in a high-speed glass blender jar containing an accurately measured volume of water, and blend for 4 ± 1 minutes. Dilute an accurately measured volume of this stock solution quantitatively and stepwise with water to obtain an Assay preparation containing about 1.25 mg of ampicillin per mL.
Procedure Proceed as directed for Procedure under Iodometric AssayAntibiotics 425. Calculate the quantity, in mg, of ampicillin (C16H19N3O4S) in each Capsule taken by the formula:
(T / D)(F / 2000)(B I)in which T is the labeled quantity, in mg, of ampicillin in each Capsule; and D is the concentration, in mg per mL, of ampicillin in the Assay preparation on the basis of the labeled quantity in each Capsule and the extent of dilution.
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USP35NF30 Page 2209Pharmacopeial Forum: Volume No. 30(1) Page 55