Ethynodiol Diacetate and Ethinyl Estradiol Tablets

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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1 DEFINITION

Ethynodiol Diacetate and Ethinyl Estradiol Tablets contain NLT 93.0% and NMT 107.0% of the labeled amount of ethynodiol diacetate (C₂₄H₃₂O₄), and NLT 90.0% and NMT 110.0% of the labeled amount of ethinyl estradiol (C₂₀H₂₄O₂).

2 IDENTIFICATION

The retention times of the ethynodiol diacetate and ethinyl estradiol peaks from the Sample solution correspond to those from the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Mobile phase: Methanol, acetonitrile, and water (3:7:10)

Standard solution: Dissolve, with the aid of sonication if necessary, quantities of USP Ethynodiol Diacetate RS and USP Ethinyl Estradiol RS in Mobile phase. Dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having known concentrations, in mg/mL, of the Reference Standards, corresponding to about 1/25 of the labeled amounts of ethynodiol diacetate and ethinyl estradiol in the Tablets.

Sample solution: Place 10 Tablets in a 250-mL volumetric flask. Add a portion of Mobile phase, and sonicate until the Tablets are completely disintegrated. Cool to room temperature, dilute with Mobile phase to volume, and filter.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 4.6-mm × 25-cm; packing L10

Flow rate: 2 mL/min

Injection size: 50 μL

System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 3000 theoretical plates for ethynodiol diacetate

Tailing factor: NMT 1.5 for ethynodiol diacetate

Relative standard deviation: NMT 2.0% for each peak due to ethynodiol diacetate and ethinyl estradiol

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₂₄H₃₂O₄ in each Tablet taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of ethynodiol diacetate from the Sample solution

r_S = peak response of ethynodiol diacetate from the Standard solution

C_S = concentration of USP Ethynodiol Diacetate RS in the Standard solution (mg/mL)

C_U = nominal concentration of ethynodiol diacetate in the Sample solution

Calculate the percentage of C₂₀H₂₄O₂ in each Tablet taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of ethinyl estradiol from the Sample solution

r_S = peak response of ethinyl estradiol from the Standard solution

C_S = concentration of USP Ethinyl Estradiol RS in the Standard solution (mg/mL)

C_U = nominal concentration of ethinyl estradiol in the Sample solution

Acceptance criteria: 93.0%–107.0% of the labeled amount of C₂₄H₃₂O₄ and 90.0%–110.0% of the labeled amount of C₂₀H₂₄O₂

4 PERFORMANCE TESTS

Disintegration 〈701〉: 15 min, the use of disks being omitted

Uniformity of Dosage Units 〈905〉: Meet the requirements for Content Uniformity with respect to ethynodiol diacetate and to ethinyl estradiol

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Ethinyl Estradiol RS

USP Ethynodiol Diacetate RS