A: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that of the Standard preparation as obtained in the Assay.

B: Transfer a quantity of finely ground Tablets, equivalent to about 50 mg of metoclopramide, to a suitable flask, add 5 mL of water, shake by mechanical means, and filter. Add to the filtrate 5 mL of a 1 in 100 solution of p-dimethylaminobenzaldehyde in 1 N hydrochloric acid: a yellow-orange color is produced.

Medium: water; 900 mL.

Apparatus 1: 50 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C14H22ClN3O2 dissolved from UV absorbances at the wavelength of maximum absorbance at about 309 nm of filtered portions of the solution under test, suitably diluted with water, if necessary, in comparison with a Standard solution having a known concentration of USP Metoclopramide Hydrochloride RS in the same medium.

Tolerances— Not less than 75% (Q) of the labeled amount of C14H22ClN3O2 is dissolved in 30 minutes.

Mobile phase, Standard preparation, System suitability solution, and Chromatographic system— Prepare as directed in the Assay under Metoclopramide Injection.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 40 mg of metoclopramide, to a 100-mL volumetric flask, add about 70 mL of 0.01 M phosphoric acid, and sonicate for 5 minutes. Cool to room temperature, dilute with 0.01 M phosphoric acid to volume, and mix. Filter the solution through a 0.45-µm filter, discarding the first portion of the filtrate. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, dilute with 0.01 M phosphoric acid to volume, and mix.

Procedure— Proceed as directed for Procedure in the Assay under Metoclopramide Injection. Calculate the quantity, in mg, of metoclopramide (C14H22ClN3O2) in the portion of Tablets taken by the formula: in which 299.80 and 336.26 are the molecular weights of metoclopramide and anhydrous metoclopramide hydrochloride, respectively; C is the concentration, in µg per mL, of USP Metoclopramide Hydrochloride RS, on the anhydrous basis, in the Standard preparation; and rU and rS are the peak responses of metoclopramide obtained from the Assay preparation and the Standard preparation, respectively.