A: Transfer a quantity of finely powdered Tablets,equivalent to about 150mg of tocainide hydrochloride,to a 100-mLvolumetric flask,add 75mLof water,shake for 15minutes,dilute with water to volume,and mix.Filter a portion of this solution,and dilute 10mLof the filtrate with water to 50mL:the UVabsorption 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 100mg of finely powdered Tablets to a suitable separator,and add 10mLof water and 2mLof 2Msodium carbonate.Extract with 20mLof methylene chloride.Add 0.3mLof filtered methylene chloride extract to 300mg of potassium bromide,and grind in an agate mortar.Evaporate to dryness under a current of air:the IRabsorption 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;750mL.

Apparatus 2: 50rpm.

Time: 30minutes.

Procedure— Determine the amount of C11H16N2O·HCl dissolved from UVabsorbances at the wavelength of maximum absorbance at about 263nm 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 RSin the same medium.

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

Procedure for content uniformity— Transfer 1Tablet to a 100-mLvolumetric flask,add 50mLof water,place in an ultrasonic bath for 20minutes,dilute with water to volume,and mix.Filter,discarding the first few mLof the filtrate.Transfer an accurately measured volume of the filtrate,equivalent to about 30mg of tocainide hydrochloride,to a 100-mLvolumetric flask,dilute with water to volume,and mix.Dissolve an accurately weighed quantity of USP Tocainide Hydrochloride RSin water,and dilute quantitatively and stepwise with water to obtain a Standard solution having a known concentration of about 300µg per mL.Concomitantly determine the absorbances of both solutions at the wavelength of maximum absorbance at about 263nm,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 Tis the labeled quantity,in mg,of tocainide hydrochloride in the Tablet,Cis the concentration,in µg per mL,of USP Tocainide Hydrochloride RSin the Standard solution,Dis 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 AUand ASare the absorbances of the solution from the Tablet and the Standard solution,respectively.

Mobile phase— Dissolve 2.16g of sodium 1-octanesulfonate in 500mLof 0.67Nacetic acid,add 500mLof methanol,and mix.Degas,and filter the solution.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

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

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of tocainide hydrochloride,to a 200-mLvolumetric flask,add 100mLof water,and place in an ultrasonic bath for 20minutes.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 á621ñ)—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 2mLper 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 1500theoretical 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 40µL)of the Standard preparationand the Assay preparationinto 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 Cis the concentration,in mg per mL,of USP Tocainide Hydrochloride RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.