Medium: 0.01 N hydrochloric acid; 900 mL.

Apparatus 2: 50 rpm.

Time: 90 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 75% (Q) of the labeled amount of C13H21N3O·HCl is dissolved in 90 minutes.

(Official January 1, 2007)

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

Assay preparation— Accurately weigh and mix the contents of 20 Capsules. Transfer an accurately weighed portion of the mixture, equivalent to about 500 mg of procainamide hydrochloride, to a 500-mL volumetric flask. Add about 350 mL of methanol to the flask, 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, dilute with Mobile phase to volume, and mix. [NOTE—Reserve the remainder of the clear supernatant for the Identification test.]

Procedure— Proceed as directed for Procedure in the Assay under Procainamide Hydrochloride. Calculate the quantity, in mg, of C13H21N3O·HCl in the portion of Capsule contents 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 peak responses obtained from the Assay preparation and the Standard preparation, respectively.