Medium: 0.1 N hydrochloric acid; 900 mL.

Apparatus 2: 50 rpm.

Time: 60 minutes.

Procedure— Determine the amount of C13H21N3O·HCl dissolved by employing UV absorption at the wavelength of maximum absorbance at about 275 nm on filtered portions of the solution under test, suitably diluted with an amount of 0.01 N sodium hydroxide that is not less than twice the volume of the portion of test solution taken, in comparison with a Standard solution having a known concentration of USP Procainamide Hydrochloride RS in the same media.

Tolerances— Not less than 80% (Q) of the labeled amount of C13H21N3O·HCl is dissolved in 60 minutes.

(Official January 1, 2007)

Mobile phase, Standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Procainamide Hydrochloride.

Assay preparation— Weigh and finely powder not less than 20 Procainamide Hydrochloride Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of procainamide hydrochloride, to a 500-mL volumetric flask, add about 350 mL of methanol, and sonicate for 10 minutes in a 40 water bath. Allow the flask to cool to room temperature, dilute with methanol to volume, and mix. Centrifuge a portion of the suspension, transfer 5.0 mL of the clear supernatant obtained to a 100-mL volumetric flask, reserving the remainder of the clear supernatant for the Identification test. Dilute with Mobile phase to volume, and mix.

Procedure— Proceed as directed for Procedure in the Assay under Procainamide Hydrochloride. Calculate the quantity of C13H21N3O·HCl in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Procainamide Hydrochloride RS in the Standard preparation, and rU and rS are the procainamide peak responses obtained from the Assay preparation and the Standard preparation, respectively.