Capsaicin
;)
6-Nonenamide,(E)-N-[(4-Hydroxy-3-methoxy-phenyl)methyl]-8-methyl.
(E)-8-Methyl-N-vanillyl-6-nonenamide [404-86-4].
»Capsaicin contains not less than 90.0percent and not more than 110.0percent of the labeled percentage of total capsaicinoids.The content of capsaicin (C18H27NO3)is not less than 55percent,and the sum of the contents of capsaicin and dihydrocapsaicin (C18H29NO3)is not less than 75percent,and the content of other capsaicinoids is not more than 15percent,all calculated on the dried basis.
Caution—Handle Capsaicin with care.Prevent inhalation of particles of it and prevent its contact with any part of the body.
Packaging and storage—
Preserve in tight containers,protected from light,and store in a cool place.
Labeling—
Label it to state the percentage content of total capsaicinoids.
Identification—
Prepare a test solution of Capsaicin in methanol containing 1mg per mL.Prepare a Standard solution of USP Capsaicin RSin methanol containing 1mg per mL.Separately apply 10-µLportions of the test solution and the Standard solution to a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatograms in a solvent system consisting of a mixture of ether and methanol (19:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chamber,and allow it to air-dry.Spray the plate with a 0.5%solution of 2,6-dibromoquinone-chlorimide in methanol,allow to stand in a chamber containing ammonia fumes,and examine the chromatograms:the blue color and the RFvalue of the principal spot obtained from the test solution correspond to those properties of the principal spot obtained from the Standard solution.
Melting range á741ñ:
between 57
and 66,but the range between beginning and end of melting does not exceed 5.
and 66,but the range between beginning and end of melting does not exceed 5.
Loss on drying á731ñ:
Dry it in vacuum over phosphorus pentoxide at 40for 5hours:it loses not more than 1.0%of its weight.
for 5hours:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 1.0%.
Content of capsaicin,dihydrocapsaicin,and other capsaicinoids—
Mobile phase—
Prepare a mixture of diluted phosphoric acid (1in 1000)and acetonitrile (600:400).Filter through a filter having a porosity of 0.5µm or finer,and degas.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard capsaicin solution—
Quantitatively dissolve an accurately weighed quantity of USP Capsaicin RSin methanol to obtain a solution having a known concentration of about 0.1mg per mL.
Standard dihydrocapsaicin solution—
Quantitatively dissolve an accurately weighed quantity of USP Dihydrocapsaicin RSin methanol to obtain a solution having a known concentration of about 0.025mg per mL.
Test solution—
Transfer about 25mg of Capsaicin,accurately weighed,to a 250-mLvolumetric flask,dilute with methanol to volume,and mix.
Chromatographic system
(see Chromatography á621ñ)—The liquid chromatograph is equipped with a 281-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L11and is maintained at a constant temperature of about 30.Adjust the flow rate to obtain a retention time of about 20minutes for the main capsaicin peak.Chromatograph the Standard capsaicin solution,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2%.
.Adjust the flow rate to obtain a retention time of about 20minutes for the main capsaicin peak.Chromatograph the Standard capsaicin solution,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2%.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard capsaicin solution,the Standard dihydrocapsaicin solution,and the Test solutioninto the chromatograph,record the chromatogram for a period of time that is twice that of the retention time of capsaicin,and measure the areas of the responses for all of the peaks.Calculate the percentage of capsaicin (C18H27NO3)in the portion of Capsaicin taken by the formula:
25,000(C/W)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Capsaicin RSin the Standard capsaicin solution,Wis the weight,in mg,of Capsaicin taken to prepare the Test solution,and rUand rSare the capsaicin peak responses obtained from the Test solutionand the Standard capsaicin solution,respectively.Not less than 55%is found.Calculate the percentage of dihydrocapsaicin (C18H29NO3)in the portion of Capsaicin taken by the formula:
25,000(C/W)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Dihydrocapsaicin RSin the Standard dihydrocapsaicin solution,Wis the weight,in mg,of Capsaicin taken to prepare the Test solution,and rUand rSare the dihydrocapsaicin peak responses obtained from the Test solutionand the Standard dihydrocapsaicin solution,respectively.The sum of the percentage of capsaicin found and of the percentage of dihydrocapsaicin found is not less than 75%.Using the chromatograms obtained from the Standard capsaicin solutionand the Test solution,calculate the percentage of other capsaicinoids in the portion of Capsaicin taken by the formula:
25,000(C/W)(rT/rS),
in which Cis the concentration,in mg per mL,of USP Capsaicin RSin the Standard capsaicin solution,Wis the weight,in mg,of Capsaicin taken to prepare the Test solution,rTis the sum of the peak responses of the capsaicinoids other than capsaicin and dihydrocapsaicin in the chromatogram obtained from the Test solution,and rSis the capsaicin peak response obtained from the Standard capsaicin solution.Not more than 15%of other capsaicinoids is found.
Auxiliary Information—
Staff Liaison:Gabriel I.Giancaspro,Ph.D.,Senior Scientist and Latin American Specialist
Expert Committee:(DSB)Dietary Supplements:Botanicals
USP28–NF23Page 336
Phone Number:1-301-816-8343