A: Transfer a quantity of finely powdered Tablets, equivalent to about 150 mg of tocainide hydrochloride, to a 100-mL volumetric flask, add 75 mL of water, shake for 15 minutes, dilute with water to volume, and mix. Filter a portion of this solution, and dilute 10 mL of the filtrate with water to 50 mL: the UV absorption spectrum of the solution so obtained exhibits a maximum at the same wavelength as that of a similar solution of USP Tocainide Hydrochloride RS, concomitantly measured.

B: Transfer about 100 mg of finely powdered Tablets to a suitable separator, and add 10 mL of water and 2 mL of 2 M sodium carbonate. Extract with 20 mL of methylene chloride. Add 0.3 mL of filtered methylene chloride extract to 300 mg of potassium bromide, and grind in an agate mortar. Evaporate to dryness under a current of air: the IR absorption spectrum of the potassium bromide dispersion so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Tocainide Hydrochloride RS.

Medium: water; 750 mL.

Apparatus 2: 50 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C11H16N2O·HCl dissolved from UV absorbances at the wavelength of maximum absorbance at about 263 nm of filtered portions of the solution under test, suitably diluted with Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Tocainide Hydrochloride RS in the same medium.

Tolerances— Not less than 80% (Q) of the labeled amount of C11H16N2O·HCl is dissolved in 30 minutes.

Procedure for content uniformity— Transfer 1 Tablet to a 100-mL volumetric flask, add 50 mL of water, place in an ultrasonic bath for 20 minutes, dilute with water to volume, and mix. Filter, discarding the first few mL of the filtrate. Transfer an accurately measured volume of the filtrate, equivalent to about 30 mg of tocainide hydrochloride, to a 100-mL volumetric flask, dilute with water to volume, and mix. Dissolve an accurately weighed quantity of USP Tocainide Hydrochloride RS in water, and dilute quantitatively and stepwise with water to obtain a Standard solution having a known concentration of about 300 µg per mL. Concomitantly determine the absorbances of both solutions at the wavelength of maximum absorbance at about 263 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of C11H16N2O·HCl in the Tablet taken by the formula: in which T is the labeled quantity, in mg, of tocainide hydrochloride in the Tablet, C is the concentration, in µg per mL, of USP Tocainide Hydrochloride RS in the Standard solution, D is the concentration, in µg per mL, of tocainide hydrochloride in the solution from the Tablet on the basis of the labeled quantity per Tablet and the extent of dilution, and AU and AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.

(Official January 1, 2007)

Mobile phase— Dissolve 2.16 g of sodium 1-octanesulfonate in 500 mL of 0.67 N acetic acid, add 500 mL of methanol, and mix. Degas, and filter the solution. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard preparation— Dissolve an accurately weighed quantity of USP Tocainide Hydrochloride RS quantitatively in water to obtain a solution having a known concentration of about 0.5 mg per mL.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of tocainide hydrochloride, to a 200-mL volumetric flask, add 100 mL of water, and place in an ultrasonic bath for 20 minutes. Dilute with water to volume, and mix. Filter the solution through a membrane filter, and use the filtrate as the Assay preparation.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the capacity factor, k¢, is greater than 1.6, the column efficiency determined from the analyte peak is not less than 1500 theoretical plates, the tailing factor for the analyte peak is not more than 2, and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 40 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C11H16N2O·HCl in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Tocainide Hydrochloride RS in the Standard preparation, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.