Exemestane 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

Exemestane Tablets contain Exemestane equivalent to NLT 90.0% and NMT 110.0% of the labeled amount of exemestane (C₂₀H₂₄O₂).

2 IDENTIFICATION

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

B. The UV absorption spectra of the Sample solution and the Standard solution exhibit maxima and minima at the same wavelengths, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Solution A: Methanol and water (5:95)

Solution B: Methanol and water (95:5)

Mobile phase: See Table 1.

Table 1

Diluent: Acetonitrile and water (50:50)

Standard solution: 0.1 mg/mL of USP Exemestane RS prepared as follows. Transfer a weighed amount of USP Exemestane RS into a suitable volumetric flask and add acetonitrile equivalent to 5% of the final volume. Sonicate to dissolve and dilute with Diluent to volume.

Sample stock solution: Nominally equivalent to 1.0 mg/mL of exemestane prepared as follows. Place 10 Tablets in a 250-mL volumetric flask. Add 100 mL of Diluent, sonicate for 15 min, and then shake mechanically for 15 min. Dilute with Diluent to volume.

Sample solution: Nominally equivalent to 0.1 mg/mL of exemestane in Diluent from Sample stock solution. Pass this solution through a suitable filter of 0.45-μm pore size and discard the first few milliliters.

3.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 247 nm. For Identification B, use a diode array detector in the range of 200–400 nm.

Column: 4.6-mm × 15-cm; 3-μm packing L1

Column temperature: 40°–50°

Flow rate: 1.0 mL/min

Injection volume: 10 μL

3.3 System suitability

Sample: Standard solution

3.4 Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of exemestane (C₂₀H₂₄O₂) in the portion of Tablets taken:

Result = (r_U/r_S) × (C_U/C_S) × 100

r_U = peak response of exemestane from the Sample solution

r_S = peak response of exemestane from the Standard solution

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

C_U = nominal concentration of exemestane in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: 5 g/L sodium dodecyl sulfate in water, do not degas; 900 mL

Apparatus 1: 100 rpm

Time: 30 min

Standard solution: 0.03 mg/mL of USP Exemestane RS prepared as follows. Transfer a weighed amount of USP Exemestane RS into a suitable volumetric flask and add methanol equivalent to 2% of the final volume. Sonicate to dissolve and dilute with Medium to volume.

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.2-μm pore size. Discard NLT 2 mL and use the filtrate for analysis.

Instrumental conditions

Mode: UV

Analytical wavelength: 250 nm

Cell length: 0.5 cm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of exemestane (C₂₀H₂₄O₂) dissolved:

Result = (A_U /A_S ) × C_S × (V/L) × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

C_S = concentration of the Standard solution (mg/mL)

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of exemestane (C₂₀H₂₄O₂) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

5.1 Organic Impurities

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

Standard stock solution: Use Standard solution in the Assay.

Standard solution: 0.3 μg/mL of USP Exemestane RS in Diluent from Standard stock solution

Sensitivity solution: 0.05 μg/mL of USP Exemestane RS in Diluent from Standard solution

5.2 System suitability

Samples: Standard solution and Sensitivity solution

5.3 Suitability requirements

Relative standard deviation: NMT 10.0%, Standard solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

5.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Tablets taken:

Result = (_Ur /r_S ) × (C_S /C_U ) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of exemestane from the Standard solution

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

C_U = nominal concentration of exemestane in the Sample solution (mg/mL)

Acceptance criteria: See Table 2.

Table 2

^a 6-Hydroxymethylandrosta-1,4-diene-3,17-dione.

^b Androsta-1,4-diene-3,6,17-trione.

^c 6-[{(Methylsulfonyl)oxy}methyl]androsta-1,4-diene-3,17-dione.

^d This is a process impurity and is listed for information only. It is controlled in the drug substance. It is not to be reported and is not to be included in the total degradation products.

^e 6α/β-Spirooxiranandrosta-1,4-diene-3,17-dione. The α and β forms are diastereomers.

^f 6α/β-Spirooxiranandrosta-1,4-diene-3,17-dione. The α and β forms are diastereomers.

^g 6α-(Methoxymethyl)androsta-1,4-diene-3,17-dione.

^h Androsta-1,4-diene-3,17-dione.

ⁱ 6-Methyleneandrosta-4-ene-3,17-dione.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Exemestane RS (USP 1-May-2021)