A: Infrared Absorption 197M.

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

10 M Ammonium acetate solution— Dissolve 77.1 g of ammonium acetate in 100 mL of water.

Mobile phase— Prepare a filtered and degassed mixture of methanol and 10 M Ammonium acetate solution (9:1). Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard solution— Dissolve an accurately weighed quantity of USP Sumatriptan Succinate Related Compound A RS in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 6.25 µg per mL.

Test solution— Transfer about 70 mg of Sumatriptan Succinate, accurately weighed, to a 25-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 282-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L3. The flow rate is about 2.0 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 5.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of sumatriptan related compound A free base in the portion of sumatriptan free base taken by the formula: in which 495.7 and 613.8 are the molecular weights of sumatriptan related compound A and sumatriptan succinate related compound A, respectively; 413.5 and 295.4 are the molecular weights of sumatriptan succinate and sumatriptan respectively; CS is the concentration, in mg per mL, of sumatriptan succinate related compound A in the Standard solution; CU is the concentration, in mg per mL, of sumatriptan succinate in the Test solution; and rU and rS are the peak responses of sumatriptan succinate related compound A obtained from the Test solution and the Standard solution, respectively: not more than 0.6% is found.

Diluent and Resolution solution— Proceed as directed in the Assay.

Buffer solution— Dissolve about 1.7 mL of dibutylamine, about 0.6 mL of phosphoric acid, and about 3.9 g of monobasic sodium phosphate dihydrate in water. Adjust with a solution of 50% (w/v) sodium hydroxide to a pH of about 7.5, dilute with water to 1000 mL, and mix.

Mobile phase— Prepare a filtered and degassed mixture of Buffer solution and acetonitrile (4:1). Make adjustments if necessary (see System Suitability under Chromatography 621).

Identification solution— Prepare a solution of USP Sumatriptan Succinate Related Impurities RS in Mobile phase having a concentration of about 3 mg per mL.

Test solution— Dissolve an accurately weighed quantity of Sumatriptan Succinate in Diluent to obtain a solution having a concentration of about 2.8 mg per mL.

Chromatographic system (see Chromatography 621)— Prepare as directed in the Assay. After making sure that the resolution criteria are met, chromatograph the Identification solution, and record the peak responses as directed for Procedure. Identify the peaks according to Table 1.

Procedure— Inject a volume (about 10 µL) of the Test solution into the chromatograph, record the chromatogram, and measure all of the peak responses. Calculate the percentage of each impurity in the portion of Sumatriptan Succinate taken by the formula: in which ri is the peak response for each impurity, and rs is the sum of the responses of all the peaks: meets the requirements given in Table 1.

Diluent— Dissolve 2.97 g of monobasic sodium phosphate in 600 mL of water, adjust with a sodium hydroxide solution (1 in 2) to a pH of 6.5, dilute with water to 750 mL, add 250 mL of acetonitrile, and mix.

Mobile phase— Dissolve 1.7 mL of dibutylamine, 0.6 mL of phosphoric acid, and 3.9 g of sodium dihydrogen phosphate dihydrate in 750 mL of water, adjust with a sodium hydroxide solution (1 in 2) to a pH of 6.5, and dilute with water to 1000 mL. Mix 800 mL of this solution with 200 mL of acetonitrile, then filter and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).

Resolution solution— Dissolve accurately weighed quantities of USP Sumatriptan Succinate RS and USP Sumatriptan Succinate Related Compound C RS in Diluent to obtain a solution having known concentrations of about 0.28 mg per mL and 0.14 mg per mL, respectively.

Standard preparation— Dissolve an accurately weighed quantity of USP Sumatriptan Succinate RS in Diluent to obtain a solution having a known concentration of about 0.14 mg per mL.

Assay preparation— Dissolve an accurately weighed quantity of Sumatriptan Succinate in Diluent to obtain a solution having a concentration of about 0.14 mg per mL.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 282-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.9 for sumatriptan succinate related compound C and 1.0 for sumatriptan; and the resolution, R, between sumatriptan succinate related compound C and sumatriptan is not less than 1.5. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 1.5%.

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 areas for the major peaks. Calculate the quantity of C14H21N3O2S·C4H6O4, in percentage, in the portion of Sumatriptan Succinate taken by the formula: in which CS and CU are the concentrations, in mg per mL, of sumatriptan succinate in the Standard preparation and the Assay preparation, respectively; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.