Mometasone Furoate Ointment

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

Mometasone Furoate Ointment is Mometasone Furoate in a suitable ointment base. It contains NLT 90.0% and NMT 110.0% of the labeled amount of mometasone furoate (C₂₇H₃₀Cl₂O₆).

2 IDENTIFICATION

2.1 A.

The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, both relative to the internal standard, as obtained in the Assay.

2.2 B. Thin-Layer Chromatography

(See Chromatography 〈621〉, Thin-Layer Chromatography.)

Standard solution: 0.6 mg/mL of USP Mometasone Furoate RS in methanol

Sample solution: Transfer the equivalent to 3 mg of mometasone furoate from Ointment to a 50-mL screw-capped centrifuge tube. Pipet 5.0 mL of methanol into the tube, and attach the cap. Heat in a steam bath until the Ointment completely melts, and shake vigorously until the Ointment resolidifies. Place in an ice-water bath for 10 min. Centrifuge, and filter a portion of the supernatant. Extract 1 mL of the filtrate with 1 mL of hexane, and use the lower phase.

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 10 µL

Developing solvent system A: Methanol

Developing solvent system B: Chloroform and ethyl acetate (3:1)

Analysis

Samples: Standard solution and Sample solution

Allow the spots to dry, and develop the chromatogram in Developing solvent system A until the solvent front has moved 2 cm from the origin. Remove the plate from the developing chamber, and air-dry. Develop the chromatogram in Developing solvent system B until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the spots to air-dry. Examine the plate under short-wavelength UV light.

Acceptance criteria: The Rf value of the principal spot of the Sample solution corresponds to that of the Standard solution.

3 ASSAY

3.1 Procedure

[Note-Protect from light.]

Diluent A: Tetrahydrofuran and glacial acetic acid (100:1)

Diluent B: Acetonitrile, water, and glacial acetic acid (50:50:1)

Solution A: Water

Solution B: Acetonitrile

Mobile phase: See Table 1.

Table 1

Internal standard solution: 1.4 mg/mL of diethyl phthalate in acetonitrile

Standard stock solution: 0.2 mg/mL of USP Mometasone Furoate RS in Diluent A

Standard solution: 0.05 mg/mL of mometasone furoate and 0.35 mg/mL of diethyl phthalate from equal quantities of the Standard stock solution and the Internal standard solution, in Diluent B

Sample solution: Transfer a portion of Ointment, equivalent to 1.0 mg of mometasone furoate, to a 50-mL, screw-capped centrifuge tube. Add 5.0 mL of Diluent A and a few glass beads, and mix on a vortex mixer. Add 5.0 mL of Internal standard solution, and mix. Add 10.0 mL of Diluent B, mix on a vortex mixer for 1 min, and centrifuge for 10 min. Pass the aqueous phase through a polypropylene filter of 0.2-µm pore size, discarding the first 1–2 mL of filtrate.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 254 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L60
• Flow rate: 2 mL/min
• Injection size: 20 µL

System suitability

• Sample: Standard solution
• [Note-The relative retention times for diethyl phthalate and mometasone furoate are 0.4 and 1.0, respectively.]
• Suitability requirements
• Tailing factor: NMT 1.5 for the mometasone furoate peak
• Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of mometasone furoate (C₂₇H₃₀Cl₂O₆) in the portion of Ointment taken:

Result = (Rᵤ/Rₛ) × (Cₛ/Cᵤ) × 100

Rᵤ = ratio of the mometasone furoate peak response to the diethyl phthalate peak response from the Sample solution

Rₛ = ratio of the mometasone furoate peak response to the diethyl phthalate peak response from the Standard solution

Cₛ = concentration of USP Mometasone Furoate RS in the Standard solution (mg/mL)

Cᵤ = nominal concentration of mometasone furoate in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

4.1 Organic Impurities

[Note-Protect from light.]

Diluent A, Solution A, Solution B, Mobile phase, and Standard stock solution: Prepare as directed in the Assay.

Diluent C: Acetonitrile, water, and glacial acetic acid (30:70:1)

System suitability solution: 0.1 µg/mL of USP Mometasone Furoate RS from Standard stock solution in Diluent C

Sample solution: Transfer a portion of Ointment, equivalent to 2.0 mg of mometasone furoate, to a 50-mL, screw-capped centrifuge tube. Add 5.0 mL of Diluent A and a few glass beads, and mix on a vortex mixer. Add 15.0 mL of Diluent C, and mix. Centrifuge for 10 min. Pass the aqueous phase through a polypropylene filter of 0.2-µm pore size, discarding the first 1–2 mL of filtrate.

Blank solution: Diluent C and Diluent A (3:1)

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 254 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L60
• Column temperature: 25 ± 5°
• Flow rate: 2 mL/min
• Injection size: 50 µL

System suitability

• Sample: System suitability solution
• Suitability requirements
• Relative standard deviation: NMT 10%

Analysis

Samples: System suitability solution, Sample solution, and Blank solution

[Note-Exclude any peak areas less than those from the chromatogram of the System suitability solution. Also exclude any peaks with the same retention time as that observed in the chromatogram of the Blank solution. Any peaks having a relative retention time of about 1.04 or 1.13 are controlled in the monograph for Mometasone Furoate, and therefore are not included in the total specified and unspecified impurities limit.]

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

Result = (r_U/r_T) × 100

r_U = peak response of each impurity from the Sample solution

r_T = sum of all the peak responses from the Sample solution

Acceptance criteria: See Table 2.

Table 2

5 PERFORMANCE TESTS

Minimum Fill 〈755〉: Meets the requirements

6 SPECIFIC TESTS

Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉: It meets the requirements of the tests for absence of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella species.

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Mometasone Furoate RS