Orbifloxacin Tablets
» Orbifloxacin Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of orbifloxacin (C19H20F3N3O3).
Packaging and storage— Preserve in tight containers, and store between 2 and 30.
Labeling— Label to indicate that it is for veterinary use only.
USP Reference standards 11—
USP Orbifloxacin RS
Identification—
Absorbent: silica gel.
Diluent: a mixture of chloroform, methanol, and glacial acetic acid (8:1:1).
Test solution— Crush 1 Tablet and transfer into a centrifuge tube. Add Diluent quantitatively, and mix to obtain a final concentration of about 0.56 mg per mL of orbifloxacin. Centrifuge the solution.
Standard solution— Prepare a solution of USP Orbifloxacin RS in Diluent having a concentration of about 0.56 mg per mL.
Application volume: 5 µL
Developing solvent system: a mixture of chloroform, methanol, water, and ammonium hydroxide (18:7:1:0.02).
B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Dissolution 711—
Medium: 0.1 N hydrochloric acid; 1000 mL.
Apparatus 2: 50 rpm.
Time: 30 minutes.
Determine the amount of C19H20F3N3O3 dissolved by employing the following procedure.
Standard solution— Prepare a solution of USP Orbifloxacin RS in Medium with a final concentration of about L/100, where L is the Tablet label claim in mg. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, dilute with Medium to volume, and mix.
Test solution— Pass a portion of the solution under test through a suitable 0.8-µm filter, discarding the first 3 mL.
Procedure— Determine the amount of C19H20F3N3O3 dissolved by employing UV absorption at the wavelength of maximum absorbance at about 291 nm on portions of the Test solution in comparison with the Standard solution using Medium as blank. Calculate the amount of orbifloxacin dissolved by the formula:
100,000(AU /AS)(CS /L)
in which AU and AS are the absorbances obtained with the Test solution and the Standard solution, respectively; CS is the concentration, in mg per mL, of orbifloxacin in the Standard solution; and L is the Tablet label claim in mg.
Tolerances— Not less than 80% (Q) of the labeled amount of C19H20F3N3O3 is dissolved in 30 minutes.
Uniformity of dosage units 905: meet the requirements.
Water, Method Ic 921: between 3.5% and 7.0%.
Test preparation— Accurately weigh 5 Tablets, and transfer into a 50-mL centrifuge tube. Add 25 mL of anhydrous methanol, and cap.
Blank: 25 mL of anhydrous methanol in a 50-mL centrifuge tube.
Procedure— Rotate the Test preparation and the Blank for 16 hours. Centrifuge. Titrate an equal volume of the Test preparation and the Blank so that the amount of water titrated will be approximately 1000 µg to 1500 µg.
Chromatographic purity—
Buffer, Mobile phase, Standard preparation, System suitability preparation, and Chromatographic system— Prepare as directed in the Assay.
Standard solution— Dilute quantitatively with Buffer the Standard preparation to obtain a solution having a known concentration of about 0.00004 mg per mL.
Test solution— Transfer 10 Tablets into a volumetric flask. Add Buffer to fill the flask about 70%, shake for 2 hours, and sonicate for 5 minutes. Dilute quantitatively, and stepwise if necessary, with Buffer to obtain a solution having a concentration of about 0.22 mg per mL. Pass a portion of the solution through a 0.8-µm filter.
Chromatographic system (see Chromatography 621)— Inject the Buffer as directed for Procedure to verify that there are no interfering peaks.
Procedure— Separately inject equal volumes (about 10 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the area responses for the major peaks. Calculate the percentage of related compounds in the portion of Tablets taken by the formula:
100(CS / CT)(ri / rS )(1 / F)
in which CS is the concentration, in mg per mL, of USP Orbifloxacin RS in the Standard solution; CT is the concentration, in mg per mL, of the Test solution; ri is the peak area response for each impurity obtained from the Test solution; rS is the peak area response for the orbifloxacin peak obtained from the Standard solution; and F is the relative response factor for each impurity, as presented in Table 1.
Table 1
Component Relative Retention Time Relative Response Factor (F) Limit (%)
cis-1-Cyclopropyl-7-(3,5-dimethyl-1-piperazinyl)-5,6,8-trifluoro-4(1H)-quinolinone 0.57 0.29 NMT 0.5
Orbifloxacin 1.0 1.00 —
cis-1-Cyclopropyl-7-(3,5-dimethyl-1-piperazinyl)-6,8-difluoro-1,4-dihydro-5-hydroxy-4-oxo-3-quinolinecarboxylic acid 2.9 0.71 NMT 0.5
All other related compounds and impurities — 0.11 NMT 0.5
Total known and unknown — — NMT 1
Assay—
Buffer— In a 2-L flask, dissolve about 11.8 g of sodium citrate in 1600 mL of water, and mix. Add 180 mL of glacial acetic acid, and mix. Adjust with 6 N sodium hydroxide to a pH of 3.5, dilute with water to volume, and mix.
Mobile phase— Prepare a filtered and degassed mixture of Buffer, methanol, and dioxane (91:6:4). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard stock preparation— Dissolve an accurately weighed quantity of USP Orbifloxacin RS in Buffer, and dilute quantitatively, and stepwise if necessary, with Buffer to obtain a solution having a known concentration of about 0.2 mg per mL.
Standard preparation— Accurately transfer a quantity of Standard stock preparation and dilute quantitatively, and stepwise if necessary, with Buffer to obtain a solution having a known concentration of about 0.02 mg per mL.
System suitability preparation— Dissolve about 40 mg of methyl 4-aminobenzoate in 2 mL of methanol, and dilute with Buffer to 200 mL. Pipet 10.0 mL of this solution and 10.0 mL of the Standard stock preparation into a 100-mL volumetric flask. Dilute with Buffer to volume, and mix.
Assay preparation— Transfer 10 Tablets into a volumetric flask. Add Buffer to fill the flask about 70%, shake for 2 hours, and sonicate for 5 minutes. Dilute quantitatively, and stepwise if necessary, with Buffer to obtain a solution having a known concentration of about 0.02 mg per mL. Pass a portion of the solution through a 0.8-µm filter.
Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 290-nm detector and 4.6-mm × 3-cm column that contains 3-µm packing L1. The flow rate is about 0.8 mL per minute. Chromatograph the System suitability preparation, and record the peak response as directed for Procedure: the relative retention times are about 1.3 for methyl 4-aminobenzoate and 1.0 for orbifloxacin; the resolution, R, between methyl 4-aminobenzoate and orbifloxacin is not less than 2; the tailing factor is not more than 1.8; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the area responses for the major peaks. Calculate the quantity, in mg, of orbifloxacin (C19H20F3N3O3) in the portion of Tablets taken by the formula:
C(DU)(rU / rS)
in which C is the concentration, in mg per mL, of USP Orbifloxacin RS in the Standard preparation; DU is the dilution factor of the Assay preparation, in mL; and rU and rS are the peak area responses obtained from the Assay preparation and the Standard preparation, respectively.
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