Curcuminoids Tablets
Curcuminoids Tablets are prepared from Curcuminoids and contain NLT 90.0% and NMT 110.0% of the labeled amount of curcuminoids, calculated as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin.
•  A. Thin-Layer Chromatography
Standard solution:  0.2 mg/mL of USP Curcuminoids RS in acetone
Sample solution:  Weigh and finely powder NLT 20 Tablets. Transfer a portion of the powder, equivalent to about 10 mg of curcuminoids, to a suitable container, add 5 mL of acetone, shake for 1 min, and sonicate for 10 min. Allow to stand for 15 min before use.
Adsorbent:  Chromatographic silica gel mixture with an average particle size of 10-15 µm (TLC plates)
Application volume:  10 µL, as bands
Developing solvent system:  Chloroform, methanol, and formic acid (96:4:1)
Samples:  Standard solution and Sample solution
Apply the samples as bands to a suitable thin-layer chromatographic plate (see Chromatography 621). Use a saturated chamber. Develop the chromatograms until the solvent front has moved up about three-fourths of the length of the plate. Remove the plate from the chamber, dry, and examine under UV light at 365 nm.
Acceptance criteria:  The Sample solution chromatogram shows yellowish-brown bands due to bisdesmethoxycurcumin, desmethoxycurcumin, and curcumin at RF values of about 0.4, 0.6, and 0.7, respectively, corresponding in position and color to those obtained from the Standard solution.
•  B. The retention times of the peaks for curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin of the Sample solution correspond to those of the Standard solution for the appropriate USP Reference Standard, as obtained in the test for Content of Curcuminoids.
•  Content of Curcuminoids
Mobile phase:  Tetrahydrofuran and 1 mg/mL of citric acid in water (4:6)
[Note—Sonication may be necessary to dissolve the RS in each Standard solution; all solutions should be passed through a filter with 0.45-µm pore size before injection. USP Curcumin RS, USP Desmethoxycurcumin RS and USP Bisdesmethoxycurcumin RS can also be prepared in one standard solution containing the final concentration specified below for each. ]
Standard solution A:  40 µg/mL of USP Curcuminoids RS in Mobile phase
Standard solution B:  40 µg/mL of USP Curcumin RS in Mobile phase
Standard solution C:  10 µg/mL of USP Desmethoxycurcumin RS in Mobile phase
Standard solution D:  2 µg/mL of USP Bisdesmethoxycurcumin RS in Mobile phase
Sample stock solution:  Weigh and finely powder NLT 20 Tablets. Transfer an accurately weighed amount of the powder, equivalent to about 20 mg of curcuminoids, to a 50-mL volumetric flask. Add about 30 mL of acetone, sonicate for 30 min, dilute with acetone to volume, mix, and centrifuge.
Sample solution:  Dilute a portion of the Sample stock solution (1 in 10) with Mobile phase, and mix.
Chromatographic system 
Mode:  LC
Detector:  UV-Vis 420 nm
Column:  4.6-mm × 20-cm; 5-µm packing L1
Flow rate:  1 mL/min
Injection size:  20 µL
System suitability 
Sample:  Standard solution A
[Note—The relative retention times for the curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin peaks are about 1.0, 1.2, and 1.4, respectively. ]
Suitability requirements 
Chromatogram similarity:  The chromatogram from Standard solution A is similar to the Reference Chromatogram provided with the lot of USP Curcuminoids RS being used.
Resolution:  NLT 2.0 between the curcumin and desmethoxycurcumin peaks and the desmethoxycurcumin and bisdesmethoxycurcumin peaks
Tailing factor:  NMT 1.5 for the bisdesmethoxycurcumin, desmethoxycurcumin, and curcumin peaks
Relative standard deviation:  NMT 2.0% for desmethoxycurcumin peak, in repeated injections
Samples:  Standard solution A, Standard solution B, Standard solution C, Standard solution D, and Sample solution
Calculate the quantity, in mg, of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin in each Tablet:
Result = (rU/rS) × CS × D × V × (WF/WU)
rU== peak area for curcumin, desmethoxycurcumin, or bisdesmethoxycurcumin from the Sample solution
rS== peak area for curcumin, desmethoxycurcumin, or bisdesmethoxycurcumin from the appropriate Standard solution
CS== concentration of the appropriate Standard solution (mg/mL)
D== dilution factor to prepare the Sample solution from the Sample stock solution
V== volume of Sample solution (mL)
WF== average weight of Tablets (mg)
WU== weight of Tablets powder taken to prepare the Sample stock solution (mg)
Calculate the percentage of the labeled amount of curcuminoids in the Tablet:
Result = (SQ/L) × 100
SQ== sum of the quantities of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin in the Tablet (mg)
L== labeled amount of curcuminoids (mg/Tablet)
Acceptance criteria:  90.0%–110.0% of the label claim
•  Disintegration and Dissolution 2040
Mode:  Dissolution
Medium:  Water containing 1% sodium lauryl sulfate; 900 mL
Apparatus 2:  100 rpm
Time:  60 min
Sample solution:  Combine 25-mL portions of the solution under test from each of the six dissolution vessels, and mix. Transfer 5 mL to a 25-mL volumetric flask, and dilute with Mobile phase to volume.
Analysis:  Determine the amount of curcumin (C21H20O6) dissolved by using the method used in the Content of Curcuminoids, making any necessary modifications.
Tolerances:  NLT 75% of the content of curcumin (C21H20O6) is dissolved.
•  Weight Variation 2091: Meet the requirements
•  Microbial Enumeration Tests 2021: The total aerobic bacterial count does not exceed 104 cfu/g, and the total combined molds and yeasts count does not exceed 103 cfu/g.
•  Absence of Specified Microorganisms 2022: Meet the requirements of the tests for the absence of Salmonella species and Escherichia coli
•  Packaging and Storage: Preserve in well-closed containers, protect from light and moisture, and store at room temperature.
•  Labeling: The label states the content of curcuminoids in mg/Tablet.
•  USP Reference Standards 11
USP Bisdesmethoxycurcumin RS
USP Curcumin RS
USP Curcuminoids RS
USP Desmethoxycurcumin RS
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