Test 1: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 1.

Medium: 0.25 M pH 7.4 phosphate buffer, prepared by mixing 5.175 g of monobasic sodium phosphate and 30.17 g of anhydrous dibasic sodium phosphate with water to obtain 1000 mL of solution, and adjusting by the dropwise addition of 50% sodium hydroxide solution to a pH of 7.40 ± 0.05; 900 mL.

Apparatus 2: 50 rpm.

Time: 60 minutes.

Procedure— Determine the amount of C14H10O5 dissolved from UV absorbances at the wavelength of maximum absorbance at about 308 nm of filtered portions of the solution under test, suitably diluted with the Dissolution Medium, in comparison with a Standard solution having a known concentration of USP Salsalate RS in the same medium.

Tolerances— Not less than 70% (Q) of the labeled amount of C14H10O5 is dissolved in 60 minutes.

Test 2: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.

Medium: 0.05 M, pH 7.5 phosphate buffer; prepared by mixing 40.83 g of monobasic potassium phosphate and 120 mL of 2 N sodium hydroxide with water to obtain 6 liters of solution, and adjusting by the dropwise addition of 2 N sodium hydroxide or phosphoric acid to a pH of 7.50 ± 0.05; 900 mL.

Apparatus 2: 100 rpm.

Time and Procedure— Proceed as directed for Test 1.

Tolerances— Not less than 70% (Q) of the labeled amount of C14H10O5 is dissolved in 60 minutes.

Mobile phase, Diluent, Resolution solution, and Chromatographic system— Proceed as directed in the Assay.

Standard preparation— Dissolve an accurately weighed quantity of USP Salicylic Acid RS in Diluent to obtain a stock solution having a known concentration of about 0.5 mg per mL. Transfer 3.0 mL of this solution to a 50-mL volumetric flask, dilute with Diluent to volume, and mix. This solution contains about 0.03 mg per mL.

Test preparation— Use the Assay stock solution prepared as directed in the Assay.

Procedure— Proceed as directed for Procedure in the Assay, except to inject equal volumes (about 10 µL) of the Standard preparation and the Test preparation. Calculate the percentage of salicylic acid (C7H6O3) in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Salicylic Acid RS in the Standard preparation, OT is the quantity, in mg, of salsalate in the portion of Tablets taken based on the labeled amount, and rU and rS are the salicylic acid peak responses obtained from the Test preparation and the Standard preparation, respectively: not more than 3.0% is found.

(Official January 1, 2007)

Mobile phase, Diluent, Salsalate standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Salsalate.

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 salsalate, to a 100-mL volumetric flask, dilute with Diluent to volume, and mix. Sonicate for about 10 minutes, and mix. Filter a portion of this solution through a suitable filter of 0.5 µm or finer porosity. Use the clear filtrate as the Assay stock solution. Transfer 2.0 mL of the Assay stock solution to a 100-mL volumetric flask, dilute with Diluent to volume, and mix (Assay preparation).

Procedure— Proceed as directed for Procedure in the Assay under Salsalate. Calculate the quantity, in mg, of C14H10O5 in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Salsalate RS in the Salsalate standard preparation, and rU and rS are the responses of the salsalate peaks obtained from the Assay preparation and the Salsalate standard preparation, respectively.