Test solution— Prepare an aqueous dispersion of Tablets for Oral Suspension in 0.1 N hydrochloric acid containing 4 mg of amoxicillin per mL. Use within 10 minutes of preparation.

Application: 5 µL.

Developing solvent system: a mixture of methanol, chloroform, water, and pyridine (90:80:30:1).

Procedure— Proceed as directed in the chapter. Dry the plate with the aid of a current of warm air for 10 minutes. Locate the spots on the plate by spraying lightly with a solution of ninhydrin in alcohol containing 3 mg per mL, and dry at 110 for 15 minutes.

Medium: water; 900 mL.

Apparatus 2: 75 rpm.

Time: 30 minutes.

Tolerances— Not less than 80% (Q) of the labeled amount of amoxicillin (C16H19N3O5S) is dissolved in 30 minutes.

Diluent, Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Amoxicillin.

Assay preparation— Prepare a dispersion of 20 Tablets for Oral Suspension using an accurately measured volume of water. Quantitatively dilute an accurately measured portion of the dispersion with Diluent to obtain a solution containing about 1.2 mg of amoxicillin per mL. Pass a portion of the solution through a filter having a 1-µm or finer porosity, and use the filtrate as the Assay preparation. Use this solution within 6 hours.

Procedure— Proceed as directed for Procedure in the Assay under Amoxicillin. Calculate the quantity, in mg, of amoxicillin (C16H19N3O5S) in each Tablet for Oral Suspension taken by the formula: in which L is the labeled quantity, in mg, of amoxicillin in each Tablet for Oral Suspension; D is the concentration, in mg per mL, of amoxicillin in the Assay preparation on the basis of the number of Tablets for Oral Suspension taken, the labeled quantity of amoxicillin in each Tablet for Oral Suspension, and the extent of dilution; C is the concentration, in mg per mL, of USP Amoxicillin RS in the Standard preparation; P is the potency, in µg per mg, of the USP Amoxicillin RS; and rU and rS are the amoxicillin peak responses obtained from the Assay preparation and the Standard preparation, respectively.