Flucloxacillin Capsules

Action and use

Penicillin antibacterial.

Definition

Flucloxacillin Capsules contain Flucloxacillin Sodium.

Content of flucloxacillin, C₁₉H₁₇ClFN₃O₅S

92.5 to 110.0% of the stated amount.

Identification

The infrared absorption spectrum of the contents of the capsules, Appendix II A, is concordant with the reference spectrum of flucloxacillin sodium (RS 145).

Tests

Related substances

Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) shake a quantity of the contents of the capsules containing the equivalent of 0.1 g of flucloxacillin with 80 mL of the mobile phase for 15 minutes, add sufficient of the mobile phase to produce 100 mL and filter. For solution (2) dilute 1 volume of solution (1) to 100 volumes with the mobile phase. Solution (3) contains 0.01% w/v of each of flucloxacillin sodium BPCRS and cloxacillin sodium BPCRS in the mobile phase.

The chromatographic procedure may be carried out using (a) a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Hypersil 5 ODS is suitable), (b) as the mobile phase with a flow rate of 1 mL per minute a mixture of 25 volumes of acetonitrile and 75 volumes of a 0.27% w/v solution of potassium dihydrogen orthophosphate adjusted to pH 5.0 with 2m sodium hydroxide and (c) a detection wavelength of 225 nm.

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks due to cloxacillin and flucloxacillin is at least 2.5.

For solution (1) allow the chromatography to proceed for six times the retention time of the principal peak. 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) (1%) and the sum of the areas of any such peaks is not greater than 5 times the area of the principal peak in the chromatogram obtained with solution (2) (5%). Disregard any peak with an area less than 0.05 times the area of the principal peak in the chromatogram obtained with solution (2) (0.05%).

Assay

Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) shake a quantity of the mixed contents of 20 capsules containing the equivalent of 50 mg of flucloxacillin with 40 mL of the mobile phase for 15 minutes, add sufficient of the mobile phase to produce 50 mL, filter and dilute 5 volumes of the resulting solution to 50 volumes with the mobile phase. Solution (2) contains 0.011% w/v of flucloxacillin sodium BPCRS in the mobile phase. Solution (3) contains 0.01% w/v of each of flucloxacillin sodium BPCRS and cloxacillin sodium BPCRS in the mobile phase.

The chromatographic procedure may be carried out using (a) a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Hypersil 5 ODS is suitable), (b) as the mobile phase with a flow rate of 1 mL per minute a mixture of 25 volumes of acetonitrile and 75 volumes of a 0.27% w/v solution of potassium dihydrogen orthophosphate adjusted to pH 5.0 with 2m sodium hydroxide and (c) a detection wavelength of 225 nm.

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the first peak (cloxacillin) and the second peak (flucloxacillin) is at least 2.5.

Calculate the content of C₁₉H₁₇ClFN₃O₅S in the capsules 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.