Edition: BP 2025 (Ph. Eur. 11.6 update)
General Notices
Action and use
Treatment of acne.
DEFINITION
Co-cyprindiol Tablets contain Cyproterone Acetate and Ethinylestradiol in the proportions, two thousand parts of Cyproterone Acetate and 35 parts of Ethinylestradiol.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of cyproterone acetate, C24H29ClO4
95.0 to 105.0% of the stated amount.
Content of ethinylestradiol, C20H24O2
IDENTIFICATION
A. Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
(1) To a quantity of powdered tablets containing 2 mg of Cyproterone Acetate add 1 mL of methanol (80%), shake in a water bath at 40° and disperse with the aid of ultrasound. Allow to cool, centrifuge and use the supernatant liquid.
(2) 0.0035% w/v of ethinylestradiol BPCRS and 0.2% w/v of cyproterone acetate BPCRS in methanol (80%).
CHROMATOGRAPHIC CONDITIONS
(a) Use as the coating silica gel (Merck silica gel 60 HPTLC plates are suitable).
(b) Use the mobile phase as described below.
(c) Apply 15 μL of each solution.
(d) Develop the plate to 8 cm.
(e) After removal of the plate, dry in air, spray with sulfuric acid (20%) in methanol, heat at 105° for 10 minutes and examine under ultraviolet light (365nm).
MOBILE PHASE
8 volumes of diethylamine, 32 volumes of toluene and 60 volumes of dichloromethane.
CONFIRMATION
The principal spots in the chromatogram obtained with solution (1) correspond in position and colour to those in the chromatogram obtained with solution (2).
B. In the test for Assay, the principal peaks in the chromatogram obtained with solution (1) correspond to the peaks in the
chromatogram obtained with solution (2).
TESTS
Dissolution
Comply with the dissolution test for tablets and capsules, Appendix XII B1.
TEST CONDITIONS
(a) Use Apparatus 1, rotating the basket at 50 revolutions per minute.
(b) Use 900 mL of a 0.07% w/v solution of sodium dodecyl sulfate in 0.1M hydrochloric acid, at a temperature of 37°, as the medium.
PROCEDURE
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) After 45 minutes withdraw a sample of the medium and filter. Dilute the filtrate, if necessary, with dissolution medium to produce a solution expected to contain 0.0002% w/v of Cyproterone Acetate.
(2) 0.0002% w/v of cyproterone acetate BPCRS and 0.0000035% w/v of ethinylestradiol BPCRS in dissolution medium.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (5 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (3 μm) (ODS-Hypersil is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2.5 mL per minute.
(d) Use an ambient column temperature.
(e) Use a UV detection wavelength of 282 nm and fluorimetric detection with an excitation wavelength of 280 nm and an emission wavelength of 310 nm.
(f) Inject 200 μL of each solution.
MOBILE PHASE
4 volumes of water and 6 volumes of acetonitrile.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatograms obtained with solution (1), the retention time of the peak due to cyproterone acetate is between 3.5 and 5.5 minutes and the retention time of the peak due to ethinylestradiol is between 1 and 2.5 minutes.
DETERMINATION OF CONTENT
Calculate the content of C24H29ClO4 and C20H24O2 in the medium from the chromatograms obtained and using the declared content of C24H29ClO4 in cyproterone acetate BPCRS and C20H24O2 in ethinylestradiol BPCRS, respectively.
LIMITS
The amount of Cyproterone Acetate and Ethinylestradiol released is not less than 75% (Q) of the stated amount for each component.
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions in a mixture of 9 volume of acetonitrile, 36 volumes of methanol and 55 volumes of water.
(1) To a quantity of powdered tablets containing the equivalent of 20 mg of Cyproterone Acetate and 350 μg of Ethinylestradiol, add 10 mL of a mixture of 3 volumes of acetonitrile, 4 volumes of water and 13 volumes of methanol. Heat this solution in a water bath at 40° for 15 minutes with shaking, mix with the aid of ultrasound for 30 minutes and shake for a further 20 minutes. Cool to room temperature and centrifuge. Dilute 1 volume of the supernatant liquid to 2 volumes with the same solvent mixture.
(2) Dilute 1 volume of solution (1) to 200 volumes.
(3) 0.001% w/v each of cyproterone acetate BPCRS and medroxyprogesterone acetate BPCRS.
(4) Dilute 1 volume of solution (2) to 5 volumes.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (15 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (2.7 μm) (Ascentis Express C18 is suitable).
(b) Use gradient elution and the mobile phase described below.
(c) Use a flow rate of 1 mL per minute.
(d) Use a column temperature of 40°.
(e) Use UV detection wavelengths of 260 nm and 280 nm, and fluorimetric detection with an excitation wavelength of 280 nm and an emission wavelength of 310 nm.
(f) Inject 100 μL of each solution.
MOBILE PHASE
Mobile phase A 19 volumes of acetonitrile and 81 volumes of methanol.
Mobile phase B water.
| Time (Minutes) | Mobile phase A (% v/v) | Mobile phase B (% v/v) | Comment |
| 0-30 | 45 | 55 | isocratic |
| 30-57 | 45→80 | 55→20 | linear gradient |
| 57-67 | 80→90 | 20→10 | linear gradient |
| 67-82 | 90→45 | 10→55 | linear gradient |
| 82-90 | 45 | 55 | re-equilibration |
When the chromatograms are recorded using the prescribed conditions the retention time of ethinylestradiol is about 25 minutes and the retention time of cyproterone acetate is about 46 minutes.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution between the peaks due to cyproterone acetate and medroxyprogesterone acetate is at least 1.3.
LIMITS
For Cyproterone Acetate at 280 nm:
In the chromatogram obtained with solution (1):
the area of any secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (0.5%);
the sum of the areas of all secondary peaks is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (1%).
Disregard any peak with an area less than the area of the principal peak in the chromatogram obtained with solution (4) (0.1%).
For Cyproterone Acetate at 260 nm:
In the chromatogram obtained with solution (1):
the area of any secondary peak is not more than the area of the principal peak in the chromatogram obtained with solution (2) (0.5%);
the sum of the areas of all secondary peaks is not more than twice the area of the principal peak in the chromatogram obtained with solution (2) (1%).
Disregard any peak with an area less than the principal peak in the chromatogram obtained with solution (4) (0.1%).
For Ethinylestradiol at excitation 280 nm and emission 310 nm:
In the chromatogram obtained with solution (1):
the area of any secondary peak is not more than the area of the principal peak in the chromatogram obtained with solution (2) (0.5%);
the sum of the areas of all secondary peaks is not more than twice the area of the principal peak in the chromatogram obtained with solution (2) (1%).
Disregard any peak with an area less than the principal peak in the chromatogram obtained with solution (4) (0.1%).
Uniformity of content
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Shake one tablet with the aid of ultrasound with 20 mL of methanol (80%), add sufficient methanol (80%) to produce a solution expected to contain 0.008% w/v of Cyproterone Acetate and filter.
(2) 0.008% w/v of cyproterone acetate BPCRS and 0.00014% w/v of ethinylestradiol BPCRS in methanol (80%).
(3) 0.004% w/v each of cyproterone acetate BPCRS and medroxyprogesterone acetate BPCRS in methanol (80%).
CHROMATOGRAPHIC CONDITIONS
The chromatographic conditions described under Dissolution may be used with an injection volume of 50 μL.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution between the peaks due to cyproterone acetate and medroxyprogesterone acetate is at least 1.5.
DETERMINATION OF CONTENT
Calculate the content of C24H29ClO4 and C20H24O2 in each tablet using the declared content of C24H29ClO4 in cyproterone acetate BPCRS and C20H24O2 in ethinylestradiol BPCRS, respectively.
ASSAY
Use the average of the individual results obtained in the test for Uniformity of content.
