» Salsalate Capsules contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C14H10O5.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Transfer a quantity of Capsule contents, equivalent to about 500 mg of salsalate, to a stoppered glass test tube. Add 20 mL of ether to the tube, close the tube tightly, shake by mechanical means for 10 minutes, and filter. Evaporate the filtrate to dryness using a stream of nitrogen: the IR absorption spectrum of a mineral oil dispersion of the residue thus obtained, exhibits maxima only at the same wavelengths as that of a similar preparation of USP Salsalate RS.
Disintegration 701: 30 minutes, simulated gastric fluid TS (without pepsin) being used.
Uniformity of dosage units 905: meet the requirements.
Limit of salicylic acid
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 100-mL volumetric flask, dilute with Diluent to volume, and mix. This solution contains about 0.015 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 Capsules taken by the formula:
10,000(C / OT)(rU / rS)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 Capsules 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 1.5% is found.
Mobile phase , Diluent, Salsalate standard preparation, Resolution solution, and Chromatographic systemProceed as directed in the Assay under Salsalate.
Assay preparation Transfer as completely as possible the contents of not less than 20 Capsules to a suitable tared container, and weigh. Mix, and 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 Separately inject equal volumes (about 10 µL) of the Salsalate standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the salsalate peaks. Calculate the quantity, in mg, of salsalate (C14H10O5) in the portion of Capsules taken by the formula:
5000C(rU / rS)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.
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USP35NF30 Page 4606