A: Thin-Layer Chromatographic Identification Test 201—

B: The retention times of the peaks for curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin in the chromatogram of the Test solution correspond to those in the chromatogram of the Standard solution for the appropriate USP Reference Standard, as obtained in the test for Content of curcuminoids.

Mobile phase, Standard solution 1, Standard solution 2, Standard solution 3, Standard solution 4, and Chromatographic system— Proceed as directed in the test for Content of curcuminoids under Turmeric.

Test solution— Transfer about 20 mg of curcuminoids, accurately weighed, to a 50-mL volumetric flask, add about 30 mL of acetone, and sonicate for 30 minutes. Dilute with acetone to volume, mix, and centrifuge. Transfer 5 mL of the supernatant to a 50-mL volumetric flask, dilute with Mobile phase to volume, mix, and before injection pass through a filter having a 0.45-µm porosity.

Procedure— Proceed as directed in the test for Content of curcuminoids under Turmeric. Separately calculate the percentages of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin in the portion of Curcuminoids taken by the formula: in which C is the concentration, in mg per mL, of USP Curcumin RS, USP Desmethoxycurcumin RS, or USP Bisdesmethoxycurcumin RS in the corresponding Standard solution; W is the weight, in mg, of curcuminoids taken to prepare the Test solution; rU is the peak response of the relevant analyte in the Test solution; and rS is the peak response of the relevant analyte in the corresponding Standard solution. It contains not less than 70.0% and not more than 80.0% of curcumin, not less than 15.0% and not more than 25.0% of desmethoxycurcumin, and not less than 2.5% and not more than 6.5% of bisdesmethoxycurcumin. Add the percentages due to curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin: not less than 95% is found.USP32