Desogestrel

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₂₂H₃₀O                 310.47

18,19-Dinorpregn-4-en-20-yn-17-ol, 13-ethyl-11-methylene-, (17a)-;

13-Ethyl-11-methylene-18,19-dinor-17a-pregn-4-en-20-yn-17-ol CAS RN^®: 54024-22-5.

1 DEFINITION

Desogestrel contains NLT 98.0% and NMT 102.0% of desogestrel (C₂₂H₃₀O ), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A or 197K _{▲(CN 1-May-2020)}

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Mobile phase: Acetonitrile and water (73:27)

System suitability solution: 400 µg/mL of USP Desogestrel RS and 0.4 µg/mL each of USP Desogestrel Related Compound A RS and USP Desogestrel Related Compound D RS prepared as follows. Dissolve the material in acetonitrile equivalent to 50% of the volume of a suitable volumetric flask and dilute with water to volume.

Standard solution: 400 µg/mL of USP Desogestrel RS prepared as follows. Dissolve the material in acetonitrile equivalent to 50% of the volume of a suitable volumetric flask and dilute with water to volume.

Sample solution: 400 µg/mL of Desogestrel prepared as directed in the Standard solution

3.1.1 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 205 nm

Column: 4.6-mm x 25-cm; 5-µm packing 11

Column temperature: 50°

Flow rate: 1 mL/min

Injection volume: 15 µL.

Run time: 1.5 times the retention time of desogestrel

3.1.2 System suitability

Samples: System suitability solution and Standard solution

NOTE-See Table 1 for relative retention times.]

3.1.3 Suitability requirements

Resolution: NLT 1.3 between desogestrel and desogestrel related compound A, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 0.73%, Standard solution

Peak-to-valley ratio: NLT 2.0 between desogestrel and desogestrel related compound D, System suitability solution

3.1.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of desogestrel (C₂₂H₃₀O) in the portion of Desogestrel taken:

                Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of desogestrel from the Sample solution

r_S = peak response of desogestrel from the Standard solution

C_S = concentration of USP Desogestrel RS in the Standard solution (µg/mL)

C_U = concentration of Desogestrel in the Sample solution (µg/mL) 

Acceptance criteria: 98.0%-102.0% on the dried basis

4 IMPURITIES

4.1 RESIDUE ON IGNITION (281): NMT 0.1%

4.2 ORGANIC IMPURITIES

Mobile phase, System suitability solution, Chromatographic system, and Sample solution: Proceed as directed in the Assay.

Diluent: Acetonitrile and water (50:50)

Standard stock solution: 0.04 mg/mL each of USP Desogestrel RS, USP Desogestrel Related Compound B RS, and USP Desogestrel Related Compound C RS, and 0.08 mg/mL each of USP Desogestrel Related Compound A RS and USP Desogestrel Related Compound D. RS prepared as follows. Dissolve the materials in acetonitrile equivalent to 50% of the volume of a suitable volumetric flask and dilute with water to volume.

Standard solution: 0.4 µg/mL each of USP Desogestrel RS, USP Desogestrel Related Compound B RS, and USP Desogestrel Related Compound C RS, and 0.8 µg/mL each of USP Desogestrel Related Compound A RS and USP Desogestrel Related Compound D RS in Diluent, from Standard stock solution

4.2.1 System suitability

Samples: System suitability solution and Standard solution [NOTE-See Table 1 for relative retention times.]

4.2.2 System suitability

Samples: System suitability solution and Standard solution

[NOTE-See Table 1 for relative retention times.)

4.2.3 Suitability requirements

Resolution: NLT 1.3 between desogestrel and desogestrel related compound A, System suitability solution

Relative standard deviation: NMT 5.0% for each corresponding peak present in the Standard solution

Peak-to-valley ratio: NLT 2.0 between desogestrel and desogestrel related compound D, System suitability solution

4.2.4 Analysis

Samples: Sample solution and Standard solution

Calculate the percentage of desogestrel related compound A, desogestrel related compound B, desogestrel related compound C, or desogestrel related compound D in the portion of Desogestrel taken:

                Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of desogestrel related compound A, desogestrel related compound B, desogestrel related compound C, or desogestrel related compound D from the Sample solution

r_S = peak response of the corresponding Reference Standard from the Standard solution

C_S = concentration of USP Desogestrel Related Compound A RS, USP Desogestrel Related Compound B RS, USP Desogestrel Related Compound C RS, or USP Desogestrel Related Compound D RS in the Standard solution (µg/mL)

C_U = concentration of Desogestrel in the Sample solution (µg/mL)

Calculate the percentage of 11-methylene Lynestrenol and any other individual unspecified impurity in the portion of Desogestrel taken:

                Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of 11-methylene lynestrenol or any other individual unspecified impurity from the Sample solution u

r_S = peak response of desogestrel from the Standard solution s

C_S = concentration of USP Desogestrel RS in the Standard solution (µg/mL)

C_U = concentration of Desogestrel in the Sample solution (μg/mL)

Acceptance criteria: See Table 1. Disregard peaks less than 0.05%.

Table 1

^a 11-Methylene-19-nor-17a-pregn-4-en-20-yn-17-ol.

5 SPECIFIC TESTS

5.1 OPTICAL ROTATION (781S), Procedures, Specific Rotation

Sample solution: 10 mg/mL of Desogestrel in absolute alcohol

Acceptance criteria: +53° to +57° (dried substance)

5.2 LOSS ON DRYING (731)

OFFIC Analysis: Dry under vacuum at a pressure not exceeding 15 mm of mercury at room temperature to constant weight.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant containers, and store at controlled room temperature.

USP REFERENCE STANDARDS (11)

USP Desogestrel RS

USP Desogestrel Related Compound A RS

13-Ethyl-11-methylene-18,19-dinor-5a, 17a-pregn-3-en-20-yn-17-ol;

Desogestrel A3-isomer.

C₂₂H₃₀O            310.47

USP Desogestrel Related Compound B.RS

13-Ethyl-3-hydroxy-11-methylene-18,19-dinor-17a-pregn-4-en-20-yn-17-ol.

C₂₂H₃₀O₂         326.48

USP Desogestrel Related Compound C RS

13-Ethyl-11-methylene-18,19-dinor-17a-pregn-4-en-20-yn-17-ol-3-one.

C₂₂H₂₈O₂         324.46

USP Desogestrel Related Compound D. RS

13-Ethyl-11-methylenegon-4-en-17-one.

C₂₂H₃₀O          284.44