Marbofloxacin

(Marbofloxacin for Veterinary Use, Ph Eur monograph 2233)

C₁₇H₁₉FN₄O₄    362.4    115550-35-1

Fluroquinolone antibacterial.

Ph Eur

9-Fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-pyrido[3,2,1-ij][4,1,2]benzoxadiazine-6-carboxylic acid.

99.0 per cent to 101.0 per cent (dried substance).

Light yellow, crystalline powder.

Slightly soluble in water, sparingly soluble or slightly soluble in methylene chloride, very slightly soluble in ethanol (96 per cent).

Infrared absorption spectrophotometry (2.2.24).

Comparison  marbofloxacin CRS.

Maximum 0.20, determined at 450 nm.

Dissolve 0.400 g in borate buffer solution pH 10.4 R and dilute to 10.0 mL with the same buffer solution.

Liquid chromatography (2.2.29). Carry out the test protected from light.

Solvent mixture  methanol R, water R (23:77 V/V).

Test solution  To 0.100 g of the substance to be examined add 80 mL of the solvent mixture, sonicate until dissolution and dilute to 100.0 mL with the solvent mixture.

Reference solution (a)  Dilute 5.0 mL of the test solution to 100.0 mL with the solvent mixture. Dilute 1.0 mL of this solution to 50.0 mL with the solvent mixture.

Reference solution (b)  Dissolve 10 mg of marbofloxacin for peak identification CRS (containing impurities A, B, C, D and E) in the solvent mixture and dilute to 10 mL with the solvent mixture.

• — size: l =  0.15 m, Ø = 4.6 mm;

• — stationary phase: end-capped polar-embedded octadecylsilyl amorphous organosilica polymer R (3.5 µm);

• — temperature: 40 °C.

Mobile phase  Mix 230 volumes of methanol R and 5 volumes of glacial acetic acid R with 770 volumes of a 2.70 g/L solution of sodium dihydrogen phosphate R containing 3.50 g/L of sodium octanesulfonate R and previously adjusted to pH 2.5 with phosphoric acid R.

Flow rate  1.2 mL/min.

Detection  Spectrophotometer at 315 nm.

Injection  10 µL.

Run time  2.5 times the retention time of marbofloxacin.

Identification of impurities  Use the chromatogram supplied with marbofloxacin for peak identification CRS and the chromatogram obtained with reference solution (b) to identify the peaks due to impurities A, B, C, D and E.

Relative retention  With reference to marbofloxacin (retention time = about 33 min): impurity B = about 0.5; impurity A = about 0.7; impurity C = about 0.9; impurity D = about 1.3; impurity E = about 1.5.

System suitability  Reference solution (b):

• — resolution: minimum 1.5 between the peaks due to impurity C and marbofloxacin, and minimum 4.0 between the peaks due to marbofloxacin and impurity D.

• — correction factor: for the calculation of content, multiply the peak area of impurity E by 1.5;

• — impurities C, D, E: for each impurity, not more than twice the area of the principal peak in the chromatogram obtained with reference solution (a) (0.2 per cent);

• — impurities A, B: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (a) (0.1 per cent);

• — unspecified impurities: for each impurity, not more than twice the area of the principal peak in the chromatogram obtained with reference solution (a) (0.2 per cent);

• — total: not more than 5 times the area of the principal peak in the chromatogram obtained with reference solution (a) (0.5 per cent);

• — disregard limit: the area of the principal peak in the chromatogram obtained with reference solution (a) (0.1 per cent).

Maximum 20 ppm.

Dissolve 0.5 g in dilute acetic acid R and dilute to 30 mL with the same solvent. Adding 2 mL of water R instead of 2 mL of buffer solution pH 3.5 R, the filtrate complies with test E. Prepare the reference solution using 5 mL of lead standard solution (2 ppm Pb) R.

Maximum 0.5 per cent, determined on 1.000 g by drying at 105 °C for 4 h.

Maximum 0.1 per cent, determined on 1.0 g in a platinum crucible.

Dissolve 0.300 g in 80 mL of glacial acetic acid R. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20).

1 mL of 0.1 M perchloric acid is equivalent to 36.24 mg of C₁₇H₁₉FN₄O₄.

Protected from light.

Specified impurities  A, B, C, D, E.

Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or other of the tests in the monograph. They are limited by the general acceptance criterion for other/unspecified impurities and/or by the general monograph Substances for pharmaceutical use (2034). It is therefore not necessary to identify these impurities for demonstration of compliance. See also 5.10. Control of impurities in substances for pharmaceutical use): F.

A. 6,7-difluoro-8-hydroxy-1-(methylamino)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,

B. 9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[3,2,1-ij][4,1,2]benzoxadiazine-6-carboxylic acid,

C. R = F: 6,8-difluoro-1-(methylamino)-7-(4-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,

D. R = OH: 6-fluoro-8-hydroxy-1-(methylamino)-7-(4-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,

E. R = O-C₂H₅: 8-ethoxy-6-fluoro-1-(methylamino)-7-(4-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid,

F. 4-[6-carboxy-9-fluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[3,2,1-ij][4,1,2]benzoxadiazin-10-yl]-1-methylpiperazine 1-oxide.

Ph Eur