Flumetasone and Clioquinol Ear Drops

BP 2025 (Ph. Eur. 11.6 update)

Action and use

Glucocorticoid and antibacterial.

DEFINITION

Flumetasone and Clioquinol Ear Drops contain Flumetasone Pivalate and Clioquinol.

The ear drops comply with the requirements stated under Ear Preparations and with the following requirements.

Content of flumetasone pivalate, C₂₇H₃₆F₂O₆

95.0 to 105.0% w/v of the stated amount.

Content of clioquinol, C₉H₅ClINO

95.0 to 105.0% w/v of the stated amount.

IDENTIFICATION

A. Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.

1. Disperse a quantity of the ear drops containing 1 mg of Flumetasone Pivalate in acetone, add sufficient acetone to produce 10 mL and filter.
2. 0.01% w/v of flumetasone pivalate BPCRS in acetone.

CHROMATOGRAPHIC CONDITIONS

1. Use as the coating silica gel F₂₅₄.
2. Use the mobile phase as described below.
3. Apply 50 μL of each solution.
4. Develop the plate to 15 cm.
5. After removal of the plate, dry in air, heat at 105° for 5 minutes and examine under ultraviolet light (254 nm).

MOBILE PHASE

1.2 volumes of wate, 8 volumes of methanol, 15 volumes of ether and 77 volumes of dichloromethane.

CONFIRMATION

The principal spot in the chromatogram obtained with solution (1) corresponds in position and size to that in the chromatogram obtained with solution (2).

B. In the Assay for flumetasone pivalate, the chromatogram obtained with solution (1) shows a peak with the same retention time as the peak due to flumetasone pivalate in the chromatogram obtained with solution (2).

C. In the Assay for clioquinol, the chromatogram obtained with solution (1) shows a peak with the same retention time as the peak due to clioquinol in the chromatogram obtained with solution (2).

TESTS

Related substances

For flumetasone pivalate

Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared in methanol (80%).

1. Shake a volume of the ear drops containing 1.2 mg of Flumetasone Pivalate with 50 mL of methanol (80%), add 40 mg of copper(ii) acetate and dilute to 100 mL. Place the solution in an ice bath for 1 hour, centrifuge and use the supernatant liquid.
2. Dilute 1 volume of solution (1) to 100 volumes.
3. 0.001% w/v of flumetasone pivalate BPCRS and 0.00001% w/v of flumetasone acetate.
4. Dilute 1 volume of solution (2) to 10 volumes.

CHROMATOGRAPHIC CONDITIONS

1. Use a stainless steel column (15 cm x 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 μm) (Nucleosil C18 is suitable).
2. Use isocratic elution and the mobile phase described below.
3. Use a flow rate of 1.5 mL per minute.
4. Use an ambient column temperature.
5. Use a detection wavelength of 235 nm.
6. Inject 50 μL of each solution.
7. For solution (1), allow the chromatography to proceed for 3 times the retention time of flumetasone pivalate.

MOBILE PHASE

0.2 volumes of glacial acetic acid, 20 volumes of acetonitrile, 40 volumes of methanol and 40 volumes of water.

SYSTEM SUITABILITY

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution between the peaks due to flumetasone acetate and flumetasone pivalate is at least 5.0.

LIMITS

In the chromatogram obtained with solution (1):

the area of any secondary peak is not greater than 1.5 times the area of the principal peak in the chromatogram obtained with solution (2) (1.5%);

the sum of the areas of any secondary peaks is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (2%).

Disregard any peak:

that elutes before 1.5 minutes;

with an area less than the area of the principal peak in the chromatogram obtained with solution (4) (0.1%).

For clioquinol

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

Solution A 0.1 volume of orthophosphoric acid, 10 volumes of water, 30 volumes of acetonitrile and 60 volumes of methanol.

1. Dilute a volume of the ear drops containing 18 mg of Clioquinol with 1 mL of tetrahydrofuran, add sufficient solution A to produce 100 mL, centrifuge and use the supernatant liquid.
2. Dilute 1 volume of solution (1) to 100 volumes with solution A.
3. Dilute 1 volumes of solution (2) to 5 volumes with solution A.
4. 0.018% w/v of clioquinol BPCRS and 0.00018% w/v each of 5-chloroquinolin-8-ol, 5,7-dichloroquinolin-8-ol and 5,7- diiodoquinolin-8-ol in solution A.

CHROMATOGRAPHIC CONDITIONS

1. Use a stainless steel column (25 cm x 4.6 mm) packed with octadecylsilyl silica gel for chromatography (10 μm) (Nucleosil C18 is suitable).
2. Use isocratic elution and the mobile phase described below.
3. Use a flow rate of 1 mL per minute.
4. Use an ambient column temperature.
5. Use a detection wavelength of 260 nm.
6. Inject 20 μL of each solution.
7. Allow the chromatography to proceed for twice the retention time of the peak due to clioquinol.

MOBILE PHASE

20 volumes of water and 80 volumes of methanol.

When the chromatograms are recorded under the prescribed conditions the retention times relative to clioquinol (retention time about 5 min) are: 5-chloroquinolin-8-ol, about 0.6; 5,7-diiodoquinolin-8-ol, about 0.8 and 5,7-dichloroquinolin-8-ol, about 1.1.

SYSTEM SUITABILITY

The test is not valid unless, in the chromatogram obtained with solution (4), the resolution between the peaks due to clioquinol and 5,7-dichloroquinolin-8-ol is at least 1.5.

LIMITS

In the chromatogram obtained with solution (1):

the area of any peak corresponding to 5-chloroquinolin-8-ol is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (2%);

the area of any peak corresponding to 5,7-diiodoquinolin-8-ol or 5,7-dichloroquinolin-8-ol is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1%);

the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (0.2%);

the sum of the areas of all secondary peaks is not greater than 3 times the area of the principal peak in the chromatogram obtained with solution (2) (3%).

Disregard any peak with an area less than half that of the principal peak in the chromatogram obtained with solution (3) (0.1%).

ASSAY

For flumetasone pivalate

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

1. Shake a weighed quantity of the ear drops containing 1.2 mg of Flumetasone Pivalate with 25 mL of the mobile phase, add 30 mg of copper(ii) acetate and dilute to 50 mL with the mobile phase. Place the solution in an ice bath for 1 hour, centrifuge and use the supernatant liquid.
2. 0.0024% w/v of flumetasone pivalate BPCRS in the mobile phase.
3. 0.001% w/v of flumetasone pivalate BPCRS and 0.00001% w/v of flumetasone acetate in the mobile phase.

CHROMATOGRAPHIC CONDITIONS

1. Use a stainless steel column (25 cm x 4.6 mm) packed with octadecylsilyl silica gel for chromatography (10 μm) (Nucleosil C18 is suitable).
2. Use isocratic elution and the mobile phase described below.
3. Use a flow rate of 1 mL per minute.
4. Use an ambient column temperature.
5. Use a detection wavelength of 254 nm.
6. Inject 20 μL of each solution.

MOBILE PHASE

20 volumes of water and 80 volumes of methanol.

SYSTEM SUITABILITY

The test is not valid unless, in the chromatogram obtained with solution (3) the resolution between the peaks due to flumetasone acetate and flumetasone pivalate is at least 1.5. If necessary adjust the concentration of methanol in the mobile phase.

DETERMINATION OF CONTENT

Determine the weight per mL of the ear drops, Appendix V G, and calculate the content of C₂₇H₃₆F₂O₆, weight in volume, using the declared content of C₂₇H₃₆F₂O₆ in flumetasone pivalate BPCRS.

For clioquinol

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

1. To a weighed quantity of the ear drops containing 18 mg of Clioquinol add 5 mL of a solution containing 1 volume of triethylamine and 1 volume of tetrahydrofuran, add sufficient of the mobile phase to produce 50 mL and centrifuge. Dilute 1 volume of the supernatant liquid to 10 volumes with the mobile phase.
2. 0.0036% w/v of clioquinol BPCRS in the mobile phase.
3. 0.0002% w/v of clioquinol BPCRS and 0.0004% w/v of 5,7-dichloroquinolin-8-ol in the mobile phase.

CHROMATOGRAPHIC CONDITIONS

1. Use a stainless steel column (25 cm x 4.6 mm) packed with octadecylsilyl silica gel for chromatography (10 μm) (Nucleosil C18 is suitable).
2. Use isocratic elution and the mobile phase described below.
3. Use a flow rate of 1 mL per minute.
4. Use an ambient column temperature.
5. Use a detection wavelength of 256 nm.
6. Inject 10 μL of each solution.

MOBILE PHASE

0.1 volume of orthophosphoric acid, 10 volumes of water, 30 volumes of acetonitrile and 60 volumes of methanol.

SYSTEM SUITABILITY

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution between clioquinol and 5,7- dichloroquinolin-8-ol is at least 1.5. If necessary adjust the concentration of methanol in the mobile phase.

DETERMINATION OF CONTENT

Determine the weight per mL of the ear drops, Appendix V G, and calculate the content of C₉H₅ClINO, weight in volume, using the declared content of C₉H₅ClINO in clioquinol BPCRS.