Levonorgestrel and Ethinyl Estradiol Tablets
DEFINITION
Levonorgestrel and Ethinyl Estradiol Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of levonorgestrel (C21H28O2) and NLT 90.0% and NMT 110.0% of the labeled amount of ethinyl estradiol (C20H24O2).
IDENTIFICATION
• A.
The retention times of the two major peaks of the Sample solution correspond to those of levonorgestrel and ethinyl estradiol in the Standard solution, as obtained in the Assay.
• B.
Finely powder 20 Tablets and transfer a portion of the powder, equivalent to 4 mg of levonorgestrel, to a suitable container. Add 250 mL of a solvent mixture consisting of isooctane and chloroform (3:1). Sonicate the mixture for 3 min, and then stir it by mechanical means for 30 min. Filter the mixture and evaporate the filtrate to dryness in a rotating vacuum evaporator. Dissolve the residue in 3 mL of chloroform, and transfer with a pipet to a 60-mL separator containing 18 mL of isooctane. Rinse the evaporator flask with an additional 3-mL portion of chloroform, and add the rinsing to the separator. Add 10 mL of 1 N sodium hydroxide, shake vigorously, and allow the layers to separate. Discard the lower aqueous phase, and filter the organic phase through 3 g of anhydrous sodium sulfate on filter paper into a 50-mL beaker. Rinse the filter with several small portions of the mixture of isooctane and chloroform (3:1), adding the filtered rinsings to the filtrate, and evaporate under nitrogen on a steam bath to dryness. Dissolve the residue in 1–2 mL of hot toluene, and transfer with a pipet to a small glass vial. Reduce the volume of the solution to 0.1 mL under nitrogen with warming. [Note—During this step, any crystals that deposit on the vial wall should be transferred to the bottom, and allowed to redissolve. ]
Store the vial containing the clear toluene solution at 4
overnight to allow crystallization to occur. Remove and discard the mother liquor with a pipet, rinse the crystals with two 0.5-mL portions of anhydrous ether, and discard the rinsings. Dry the vial containing the rinsed crystals in a vacuum desiccator at 60 for 4 h.
overnight to allow crystallization to occur. Remove and discard the mother liquor with a pipet, rinse the crystals with two 0.5-mL portions of anhydrous ether, and discard the rinsings. Dry the vial containing the rinsed crystals in a vacuum desiccator at 60 for 4 h.
Acceptance criteria:
The melting point of the dried crystals of levonorgestrel so obtained is not lower than 220, using the procedure described under Melting Range or Temperature 
741
, Class I.
, using the procedure described under Melting Range or Temperature 741, Class I.
ASSAY
• Procedure
Mobile phase:
Acetonitrile, methanol, and water (35:15:45)
Standard solution:
15 µg/mL of USP Levonorgestrel RS and 3 µg/mL of USP Ethinyl Estradiol RS in Mobile phase
Sample solution:
Transfer a number of Tablets, equivalent to 3 mg of levonorgestrel, to a 200-mL volumetric flask. Dilute with Mobile phase to volume, sonicate to disintegrate the Tablets, then shake by mechanical means for 20 min. Centrifuge, and use the clear supernatant.
Chromatographic system
Mode:
LC
Detector:
UV 215 nm
Column:
4.6-mm × 15-cm; 5- to 7-µm packing L7
Flow rate:
1 mL/min
Injection size:
50 µL
System suitability
Sample:
Standard solution
[Note—The relative retention times for ethinyl estradiol and levonorgestrel are about 0.7 and 1.0, respectively. ]
Suitability requirements
Resolution:
NLT 2.5 between the two major peaks
Relative standard deviation:
NMT 2.0%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of C21H28O2 and C20H24O2 in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response of the corresponding analyte from the Sample solution |
| rS | = | = peak response of the corresponding analyte from the Standard solution |
| CS | = | = concentration of the appropriate USP Reference Standard in the Standard solution (µg/mL) |
| CU | = | = nominal concentration of the corresponding analyte in the Sample solution (µg/mL) |
Acceptance criteria:
90.0%–110.0% of the labeled amount of C21H28O2, 90.0%–110.0% of the labeled amount of C20H24O2
PERFORMANCE TESTS
• Dissolution 711:
Determine the amount of C21H28O2 and C20H24O2 dissolved by employing the following method.
711:
Determine the amount of C21H28O2 and C20H24O2 dissolved by employing the following method.
Medium:
Polysorbate 80 (5 µg/g) in water; 500 mL
Apparatus 2:
75 rpm
Time:
60 min
Mobile phase:
Acetonitrile and water (6:4)
Standard solution:
Prepare a solution of USP Levonorgestrel RS and USP Ethinyl Estradiol RS in Medium having known concentrations corresponding approximately to the concentrations that would be obtained by dissolving 1 Tablet in 500 mL of Medium.
[Note—A volume of alcohol not exceeding 2% of the final total volume of solution may be used to aid in dissolving the Reference Standards. ]
Sample solution:
Withdraw 15-mL portions of liquid from each vessel, and pass through a polyvinylidene filter, discarding the first 10 mL of the filtrate.
Chromatographic system
Mode:
LC
Detector:
UV 247 nm (for levonorgestrel analysis); a spectrofluorometric detector (for ethinyl estradiol analysis), with an excitation wavelength of 285 nm, and an emission wavelength of 310 nm
Column:
4-mm × 15-cm; packing L7
Flow rate:
1 mL/min
Injection size:
100 µL
System suitability
Sample:
Standard solution
[Note—The relative retention times for ethinyl estradiol and levonorgestrel are about 0.7 and 1.0, respectively. ]
Suitability requirements
Relative standard deviation:
NMT 3.0%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of C21H28O2 and C20H24O2 dissolved:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response of the corresponding analyte from the Sample solution |
| rS | = | = peak response of the corresponding analyte from the Standard solution |
| CS | = | = concentration of the appropriate USP Reference Standard in the Standard solution (µg/mL) |
| CU | = | = nominal concentration of the corresponding analyte in the Sample solution (µg/mL) |
Tolerances
Uncoated Tablets:
NLT 80% (Q) of the labeled amount of C21H28O2, and 75% (Q) of the labeled amount of C20H24O2 is dissolved.
Coated Tablets:
NLT 60% (Q) of the labeled amount of C21H28O2 and C20H24O2 is dissolved.
• Uniformity of Dosage Units 905:
Meet the requirements
905:
Meet the requirements
Sample solution:
Place 1 Tablet in a 40-mL centrifuge tube, add 10.0 mL of Mobile phase, and proceed as directed in the Assay.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Mary S. Waddell
Scientific Liaison 1-301-816-8124 |
(SM42010) Monographs - Small Molecules 4 |
| 711 |
Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison 1-301-816-8106 |
(GCDF2010) General Chapters - Dosage Forms |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 3674
Pharmacopeial Forum: Volume No. 36(1) Page 117