BP 2025 (Ph. Eur. 11.6 update)
Action and use
Penicillin antibacterial.
DEFINITION
Flucloxacillin for Injection is a sterile material consisting of Flucloxacillin Sodium Monohydrate with or without excipients. It is supplied in a sealed container.
The contents of the sealed container comply with the requirements for Powders for Injections or Infusions stated under Parenteral Preparations and with the following requirements.
Content of flucloxacillin, C19H17ClFN3O5S
95.0 to 105.0% of the stated amount.
IDENTIFICATION
A. The infrared absorption spectrum, Appendix II A, is concordant with the reference spectrum of flucloxacillin sodium (RS 145).
B. Yield reaction B characteristic of sodium salts, Appendix VI.
TESTS
Acidity or alkalinity
pH of a solution containing the equivalent of 10% w/v of flucloxacillin, 5.0 to 7.0, Appendix V L.
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions in 50% v/v acetonitrile.
Prepare the solutions protected from light.
(1) Disperse a quantity of the contents of the sealed container containing the equivalent of 0.1 g of flucloxacillin in 50% v/v of acetonitrile and dilute to 100 mL.
(2) Dilute 1 volume of solution (1) to 100 volumes.
(3) 0.001% w/v of flucloxacillin impurity D EPCRS and 0.1% w/v of flucloxacillin sodium BPCRS.
(4) 0.1% w/v of flucloxacillin for peak identification EPCRS.
(5) Dilute 1 volume of solution (2) to 10 volumes.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 μm) (Zorbax SB-C18 is suitable).
(b) Use gradient elution and the mobile phase described below.
(c) Use a flow rate of 1.5 mL per minute.
(d) Use a column temperature of 40°.
(e) Use a detection wavelength of 225 nm.
(f) Inject 10 μL of each solution.
MOBILE PHASE
Mobile phase A 0.118% w/v sodium hexanesulfonate monohydrate for ion-pair chromatography in a mixture of 0.8 volumes of concentrated ammonia and 1000 volumes of water for chromatography. Adjust the pH of the resulting solution to pH 2.9 ± 0.1 with orthophosphoric acid.
Mobile phase B acetonitrile R1.
| Time (Minutes) | Mobile phase A (% v/v) | Mobile phase B (% v/v) | Comment |
| 0-30 | 80→45 | 20→55 | linear gradient |
| 30-35 | 45→35 | 55→65 | linear gradient |
| 35-40 | 35→80 | 65→20 | linear gradient |
| 40-45 | 80 | 20 | e-equilibration |
When the chromatograms are recorded under the prescribed conditions, the relative retentions with reference to flucloxacillin (retention time about 18 minutes) are: impurity C, about 0.1; impurity A (isomer 1), about 0.48; impurity A (isomer 2), about 0.50; impurity F, about 0.55; impurity G, about 0.65; impurity B (isomer 1), about 0.75; impurity B (isomer 2), about 0.8; impurity D, about 0.9; impurity H, about 1.2; impurity E, about 1.25; impurity I, about 1.35; impurity J, about 1.55 and impurity K, about 1.6.
SYSTEM SUITABILITY
The test is not valid unless:
in the chromatogram obtained with solution (3), the resolution between impurity D and flucloxacillin is at least 1.5.
in the chromatogram obtained with solution (5), the signal-to-noise ratio of the principal peak is at least 40.
LIMITS
Identify any peak corresponding to impurities B and C in the chromatogram obtained with solution (1), using the chromatogram obtained with solution (4), and multiply the area of these peaks by a correction factor of 1.3 and 4.2 respectively.
In the chromatogram obtained with solution (1):
the sum of the areas of any peaks corresponding to impurity A is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (2%);
the sum of the areas of any peaks corresponding to impurity B is not greater than 1.5 times the area of the principal peak in the chromatogram obtained with solution (2) (1.5%);
the area of any peaks corresponding to impurity C or E is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1%);
the area of any peak corresponding to impurity H is not greater than 0.5 times the area of the principal peak in the chromatogram obtained with solution (2) (0.5%);
the area of any peaks corresponding to impurity F, I, J or K is not greater than 0.4 times the area of the principal peak in the chromatogram obtained with solution (2) (0.4%);
the area of any peaks corresponding to impurity D or G is not greater than 0.3 times the area of the principal peak in the chromatogram obtained with solution (2) (0.3%);
the area of any other secondary peak is not greater than 0.2 times the area of the principal peak in the chromatogram obtained with solution (2) (0.2%);
the sum of the areas of all secondary peaks is not greater than 5 times the area of the principal peak in the chromatogram obtained with solution (2) (5.0%).
Disregard any peak with an area less than the area of the principal peak in the chromatogram obtained with solution (5) (0.1%).
Bacterial endotoxins
Carry out the test for bacterial endotoxins, Appendix XIV C. Dissolve the contents of the sealed container in water BET to give a solution containing the equivalent of 9 mg of flucloxacillin per mL (solution A). The endotoxin limit concentration of solution A is less than 0.35 IU per mL.
ASSAY
Determine the weight of the contents of 10 containers as described in the test for uniformity of weight, Appendix XII C1, Powders for Parenteral Administration.
Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared in 50% v/v of acetonitrile.
(1) Disperse a quantity of mixed contents of the 10 containers, containing the equivalent of 0.5 g of flucloxacillin in 50% v/v of acetonitrile and dilute to 200 mL. Dilute 1 volume of the resulting solution to 25 volumes.
(2) 0.011% w/v of flucloxacillin sodium BPCRS.
(3) 0.0001% w/v of flucloxacillin impurity D EPCRS and 0.01% w/v of flucloxacillin sodium BPCRS.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 μm)
(Zorbax SB-C18 is suitable).
(b) Use gradient elution and the mobile phase described below.
(c) Use a flow rate of 1.8 mL per minute.
(d) Use a column temperature of 40°.
(e) Use a detection wavelength of 225 nm.
(f) Inject 10 μL of each solution.
MOBILE PHASE
Mobile phase A 0.118% w/v sodium hexanesulfonate monohydrate for ion-pair chromatography in a mixture of 0.8 volumes of concentrated ammonia and 1000 volumes of water. Adjust the pH of the resulting solution to pH 3.1 ± 0.1 with orthophosphoric acid.
Mobile phase B acetonitrile R1.
| Time (Minutes) | Mobile phase A (% v/v) | Mobile phase B (% v/v) | Comment |
| 0-8 | 65→41 | 35→59 | linear gradient |
| 8-12 | 41→65 | 59→35 | linear gradient |
| 12-18 | 65 | 35 | re-equilibration |
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution between impurity D and flucloxacillin is at least 1.5.
DETERMINATION OF CONTENT
Calculate the content of C19H17ClFN3O5S in a container of average content weight using the declared content of C19H16ClFN3NaO5S in flucloxacillin sodium BPCRS. Each mg of C19H16ClFN3NaO5S is equivalent to 0.9538 mg of C19H17ClFN3O5S .
LABELLING
The quantity of active ingredient is stated in terms of the equivalent amount of flucloxacillin.
IMPURITIES
The impurities limited by the requirements of this monograph include those listed under Flucloxacillin Sodium Monohydrate.
