Identification, Ultraviolet-Visible Absorption 
197U
—
FOR OILY PREPARATIONS—
Spectral range:
300 to 700 nm.
Solution—
Prepare as directed below for the Test solution in Content of lycopene (test for oily preparations).
Ratio:
A476 / A508 between 1.10 and 1.14 in cyclohexane.
FOR SOLID PREPARATIONS—
Spectral range:
300 to 700 nm.
Solution—
Prepare as directed below for the Test solution in Content of lycopene (test for solid preparations).
Ratio:
A472 / A504 between 1.09 and 1.13 in isopropyl alcohol.
Content of all-E-lycopene, 5Z-lycopene, and related compounds—
Mobile phase, Standard solution, and Chromatographic system—
Proceed as directed for
Content of all-E-lycopene, 5Z-lycopene, and related compounds under
Lycopene.
Test solution for oil preparations
—Transfer a quantity of oil Preparation, equivalent to about 15 mg of lycopene, to a 25-mL volumetric flask, and dissolve in tetrahydrofuran containing 50 mg of butylated hydroxytoluene per L. Dilute with the same solvent to volume. Pipet 2 mL into a 50-mL volumetric flask, and add 8 mL of tetrahydrofuran. Dilute with tert-butyl methyl ether to volume. Use this solution for injection.
Test solution for solid preparations
—Transfer a quantity of solid Preparation, equivalent to 5 mg of lycopene, into a 250-mL volumetric flask, and add about 60 units of bacterial alkaline protease preparation or another suitable enzyme and about 25 mg of butylated hydroxytoluene. Add 2.5 mL of water, place in an ultrasonic bath at 50
for 10 minutes, and shake occasionally until the material is finely divided with no lumps. Add 5 mL of tetrahydrofuran and 40 mL of dehydrated alcohol, and place again for about 1 minute in the ultrasonic bath. Cool to room temperature, and dilute with
tert-butyl methyl ether to volume. Shake vigorously. Allow the precipitate to settle, and filter the supernatant.
Procedure—
Proceed as directed for
Content of all-E-lycopene, 5Z-lycopene, and related compounds under
Lycopene. Calculate the percentage of related compounds in the portion of Lycopene Preparation taken by the formula:
rs / rT ,
in which
rs is the sum of the responses of all peaks except the peak for all-
E-lycopene and the peak for 5
Z-lycopene, and
rT is the total detected area in the chromatogram: not more than 14.0% of other related compounds calculated as lycopene is found. Calculate the percentage of the 5
Z-lycopene isomer in the portion of Lycopene Preparation taken by the formula:
r5Z / rT ,
in which
r5Z is the peak response for the 5
Z-lycopene isomer, and the other terms are as described above: not more than 23.0% of the 5
Z-lycopene isomer is found. Calculate the percentage of all-
E-lycopene in the portion of Lycopene Preparation taken by the formula:
rE / rT ,
in which
rE is the peak response of the all-
E-lycopene isomer, and the other terms are as described above: not less than 65.0% of all-
E-lycopene is found.
Content of lycopene—
TEST FOR OILY PREPARATIONS—
Test stock solution—
Transfer an accurately weighed quantity of Lycopene Preparation containing about 25 mg of lycopene to a 100-mL volumetric flask, and add about 25 mg of butylated hydroxytoluene and about 60 mL of methylene chloride. Sonicate to dissolve, and dilute with methylene chloride to volume.
Test solution
—Transfer 2.0 mL of the Test stock solution to a 200-mL volumetric flask, and dilute with cyclohexane to volume.
Procedure—
Determine the absorbance of the
Test solution at the wavelength of maximum absorbance at about 476 nm, using cyclohexane as the blank. Calculate the percentage of lycopene in the portion of Lycopene Preparation taken by the formula:
1000A/331W,
in which
A is the absorbance of the
Test solution; W is the weight, in g, of the portion of Lycopene Preparation taken to prepare the
Test stock solution; and 331 is the absorptivity of the pure lycopene in cyclohexane.
TEST FOR SOLID PREPARATIONS—
Test stock solution—
Transfer an accurately weighed quantity of Lycopene Preparation containing about 5 mg of lycopene into a 200-mL volumetric flask. Add about 60 units of bacterial alkaline protease preparation or another suitable enzyme and about 25 mg of butylated hydroxytoluene. Add 2.5 mL of diluted ammonium hydroxide (2 in 100). Incubate in a water bath (about 40
) until the matrix has dissolved (about 1 to 2 minutes), while rotating the flask to avoid having material stick to the glass surface. Add 5 mL of tetrahydrofuran, and shake until no colored precipitate remains. Add another portion of 2 mL of tetrahydrofuran. Add 40 mL of dehydrated alcohol, and shake until the mixture is homogeneous. Add 100 mL of diethyl ether, and shake vigorously. Dilute with diethyl ether to volume, shake vigorously, and allow to stand until the solid has settled.
Test solution—
Transfer 2.0 mL of the supernatant from the Test stock solution to a 25-mL volumetric flask, and dilute with isopropyl alcohol to volume.
Procedure—
Determine the absorbance of the
Test solution at the wavelength of maximum absorbance at about 472 nm, using isopropyl alcohol as the blank. Calculate the percentage of lycopene in the portion of Lycopene Preparation taken by the formula:
250A/320W,
in which
A is the absorbance of the
Test solution; W is the weight, in g, of the portion of Lycopene Preparation taken to prepare the
Test stock solution; and 320 is the absorptivity of the pure lycopene in isopropyl alcohol.
