Norethindrone Tablets
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
1 DEFINITION
Norethindrone Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of norethindrone (C20H26O2).
2 IDENTIFICATION
A. INFRARED ABSORPTION
Analysis: Mix an amount of powdered Tablets equivalent to 50 mg of norethindrone with 15 mL of solvent hexane. Stir the solution occasionally for 15 min. Centrifuge the mixture, then decant and discard the solvent hexane. Extract the residue with two 10-mL portions of solvent hexane, centrifuging and decanting as before, and discard the solvent hexane. Add 25 mL of chloroform to the residue, mix by shaking for 1-2 min, and filter. Evaporate the filtrate to about 3 mL, add a few mL of solvent hexane to induce crystallization, and evaporate to dryness.
Acceptance criteria: The IR absorption spectrum of a potassium bromide dispersion prepared from the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Norethindrone RS.
3 ASSAY
PROCEDURE
Solution A: Dissolve 1.0 g of Isoniazid in 1000 mL of anhydrous methanol, and add 1.3 mL of hydrochloric acid.
Standard stock solution: 14 µg/mL of USP Norethindrone RS in methanol
Standard solution: Transfer 10.0 mL of the Standard stock solution to a suitable container, add 2.0 mL of Solution A, mix, seal, and allow to stand for 30 min.
Sample stock solution: Transfer an amount of finely powdered Tablets equivalent to 0.7 mg of norethindrone (powder NLT 20 Tablets) to a 50-mL volumetric flask, and add anhydrous methanol to volume. Mix, and allow to stand for 10 min, with occasional mixing. Filter a portion of the mixture to clarify the solution. Use the filtrate.
Sample solution: Transfer 10.0 mL of the Sample stock solution to a suitable container. Add 2.0 mL of Solution A, mix, seal, and allow to stand for 30 min.
Sample blank solution: Transfer 10.0 mL of the Sample stock solution to a suitable container, add 2.0 mL of methanol, and mix.
Reagent blank solution: Transfer 10.0 mL of methanol to a suitable container, add 2.0 mL of Solution A, mix, seal, and allow to stand for 30 min.
Instrumental conditions
Mode: UV
Analytical wavelength: 380 nm
Samples: Standard solution, Sample solution, Sample blank solution, and Reagent blank solution
Analysis
Concomitantly determine the absorbances of these solutions, using methanol as the reference for the Sample blank solution, and using
the Reagent blank solution as the reference for the Sample solution and the Standard solution.
Calculate the precentage of the labeled amount of norethindrone (C20H26O2) in the portion of Tablets taken:
Result = (AU − AUB )/AS × (CS /CU ) × 100
AU = absorbance of the Sample solution
AUB = absorbance of the Sample blank solution
AS = absorbance of the Standard solution
CS = concentration of USP Norethindrone RS in the Standard solution (µg/mL)
CB = nominal concentration of norethindrone in the Sample solution (µg/mL)
Acceptance criteria: 90.0%–110.0%
4 PERFORMANCE TESTS
Dissolution 〈711〉
Test 1
Medium: 0.09% Sodium lauryl sulfate in 0.1 N hydrochloric acid; 500 mL, deaerated
Apparatus 2: 75 rpm
Time: 30 min
Mobile phase: Acetonitrile and water (2:3)
Standard stock solution: 0.07 mg/mL of USP Norethindrone RS in methanol. Sonication may be used to aid dissolution.
Standard solution: (L/500) mg/mL of USP Norethindrone RS in Medium from the Standard stock solution, where L is the claim in mg/Tablet of norethindrone
Sample solution: Pass a portion of the solution under test through a suitable lter of 0.45-µm pore size.
Chromatographic system
(See Chromatography 〈621〉, System Suitability.)
Mode: LC
Detector: UV 254 nm
Column: 4.6-mm × 15-cm; 5-µm packing L7
Flow rate: 1.5 mL/min
Injection volume: 100 µL
System suitability
Sample: Standard solution
Suitability requirements
Relative standard deviation: NMT 3.0%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of norethindrone (C20H26O2) dissolved:
Result = (ru /rs ) × Cs × V × (1/L) × 100
ru = peak response from the Sample solution
rs = peak response from the Standard solution
Cs = concentration of norethindrone in the Standard solution (mg/mL)
V = volume of Medium, 500 mL
L = label claim (mg/Tablet)
Tolerances: NLT 80% (Q) of the labeled amount of norethindrone (C20H26O2) is dissolved.
Test 2: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.
Medium: 0.09% Sodium lauryl sulfate in 0.1 N hydrochloric acid; 500 mL, deaerated
Apparatus 2: 75 rpm
Time: 45 min
Mobile phase: Acetonitrile and 0.02 M phosphate buffer pH 6.0 (35:65)
Standard stock solution: 0.028 mg/mL of USP Norethindrone RS in methanol
Standard solution: (L/500) mg/mL of USP Norethindrone RS in Medium from the Standard stock solution, where L is the claim in mg/Tablet of norethindrone
Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size or centrifuge at least 10 mL of the solution under test and use the supernatant.
Use one of the following two chromatographic systems. (See Chromatography (621), System Suitability.)
Chromatographic system 1
Mode: LC
Detector: UV 200 nm
Column: 4.6-mm x 10-cm; 3-µm packing L1
Flow rate: 1 mL/min
Injection volume: 100 µL
Chromatographic system 2
Mode: LC
Detector: UV 240 nm
Column: 4.6-mm × 10-cm; 3- or 3.5-µm packing L1
Flow rate: 2 mL/min
Injection volume: 100 µL
System suitability
Use this System suitability for either Chromatographic system 1 or Chromatographic system 2.
Sample: Standard solution
Suitability requirements
Relative standard deviation: NMT 3.0%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of norethindrone (C20H26O2) dissolved:
Result = (ru /rs ) × Cs × V × (1/L) × 100
ru = peak response from the Sample solution
rs = peak response from the Standard solution
Cs = concentration of norethindrone in the Standard solution (mg/mL)
V = volume of Medium, 500 mL
L = label claim (mg/Tablet)
Tolerances: NLT 80% (Q) of the labeled amount of norethindrone (C20H26O2) is dissolved.
Test 3: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 3.
Medium: 0.5% Sodium lauryl sulfate in 0.1 N hydrochloric acid; 500 mL, deaerated
Apparatus 2: 75 rpm
Time: 20 min
Mobile phase: Acetonitrile and water (50:50)
Standard stock solution: 0.028 mg/mL of USP Norethindrone RS in methanol. Sonication may be used to aid dissolution.
Standard solution: (L/500) mg/mL of USP Norethindrone RS in Medium from the Standard stock solution, where L is the claim in mg/Tablet of norethindrone
Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-um pore size or centrifuge and use the supernatant.
Chromatographic system
(See Chromatography (621), System Suitability.)
Mode: LC
Detector: UV 240 nm
Column: 4.6-mm x 15-cm; 5-µm packing L1
Column temperature: 30°
Flow rate: 1.3 mL/min
Injection volume: 100 µL
System suitability
Sample: Standard solution
Suitability requirements
Tailing factor: NMT 2.0
Relative standard deviation: NMT 3.0%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of norethindrone (C20H26O2) dissolved:
Result = (ru /rs ) × Cs × V × (1/L) × 100
ru = peak response from the Sample solution
rs = peak response from the Standard solution
Cs = concentration of norethindrone in the Standard solution (mg/mL)
V = volume of Medium, 500 mL
L = label claim (mg/Tablet)
Tolerances: NLT 80% (Q) of the labeled amount of norethindrone (C20H26O2) is dissolved.
Uniformity of Dosage Units 〈905〉: Meet the requirements
5 ADDITIONAL REQUIREMENTS
Packaging and Storage: Preserve in well-closed containers.
Labeling: When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.
USP Reference Standards 〈11〉
