A: Infrared Absorption 197K.

B: The chromatogram of the Assay preparation obtained as directed in the Assay exhibits a major peak, the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparation.

C: A solution (1 in 100) responds to the tests for Chloride 191.

Test solution: 10 mg per mL, in water, allowed to stand for 3 hours.

Mobile phase— Mix 3 volumes of acetonitrile and 2 volumes of methanol, and allow the mixture to attain room temperature. To 270 mL of this solution in a 1-liter graduated cylinder add 20.0 mL of 25% tetramethylammonium hydroxide solution in methanol, and add water to make 1 L. Adjust with phosphoric acid to a pH of 4.0, filter, and degas.

Standard preparation— Dissolve an accurately weighed quantity of USP Tubocurarine Chloride RS in Mobile phase to obtain a solution having a known concentration of about 0.3 mg per mL.

Assay preparation— Transfer 30 mg of Tubocurarine Chloride, accurately weighed, to a 100-mL volumetric flask. Dissolve in Mobile phase, dilute with Mobile phase to volume, and mix.

System suitability preparation— Dissolve suitable quantities of tubocurarine chloride and phenol in Mobile phase to obtain a solution containing about 0.30 mg and 0.50 mg per mL, respectively.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 220-nm detector, and a 4-mm × 25-cm column that contains packing L1. The flow rate is about 1 mL per minute. Chromatograph the System suitability preparation, and record the peak responses as directed for Procedure: the resolution, R, between the two major peaks is not less than 2.0, and the tailing factor, T, for tubocurarine chloride is not more than 2.0. The relative standard deviation for replicate injections of the Standard preparation is not more than 2.0%. The relative retention times are about 0.50 and 1.0 for tubocurarine chloride and phenol, respectively.

Procedure— Separately inject equal volumes (about 10 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 C37H41ClN2O6·HCl in the portion of Tubocurarine Chloride taken by the formula: in which C is the concentration, in mg per mL, of USP Tubocurarine Chloride RS in the Standard preparation, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.