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Ofloxacin
(oh flox' a sin).
» Ofloxacin contains not less than 98.5 percent and not more than 101.5 percent of C18H20FN3O4, calculated on the dried basis.
Packaging and storage
Preserve in well-closed containers, protected from light. Store at 25
USP Reference standards
USP Ofloxacin Related Compound A RS
9-Fluoro-3-methyl-7-oxo-10-(piperazin-1-yl)-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid.
Identification
Loss on drying
Residue on ignition
Arsenic, Method II
Heavy metals, Method II
Related compounds
Diluent
Prepare a mixture of water and acetonitrile (6:1).
Mobile phase
Dissolve 4.0 g of ammonium acetate and 7.0 g of sodium perchlorate in 1300 mL of water, adjust with phosphoric acid to a pH of 2.2, and mix. Prepare a filtered and degassed mixture of this solution and 240 mL of acetonitrile. Make adjustments if necessary (see System Suitability under Chromatography
System suitability solution
Transfer 10.0 mg of USP Ofloxacin Related Compound A RS and 10.0 mg of USP Ofloxacin RS to a 100-mL volumetric flask, dissolve in and dilute with Diluent to volume, and mix. Dilute 10.0 mL of this solution with Diluent to 50.0 mL. Dilute 1.0 mL of this solution with Diluent to 50.0 mL.
Standard solution
Quantitatively dissolve an accurately weighed quantity of USP Ofloxacin RS in Diluent to obtain a solution that contains 0.0004 mg per mL of ofloxacin.
Test solution
Quantitatively dissolve an accurately weighed quantity of Ofloxacin in Diluent to obtain a solution containing about 0.2 mg per mL.
Chromatographic system (see Chromatography
Procedure
Inject equal volumes (about 10 µL) of the Test solution and the Standard solution into the chromatograph, record the chromatograms for a period of time that is about 2.5 times the retention time of the ofloxacin peak, and measure the areas for all of the peaks except the solvent peak. Calculate the percentage of each impurity with an area greater than 0.1 times the average area of the ofloxacin peak obtained from the Standard solution by the formula:
100(C/CT)(ri / rS)
in which C is the concentration, in mg per mL, of USP Ofloxacin RS in the Standard solution; CT is the concentration, in mg per mL, of Ofloxacin in the Test solution; ri is the peak area for an individual impurity; and rS is the average area of the ofloxacin peak obtained from the Standard solution: not more than 0.3% of any individual impurity is found; and the sum of all impurities found is not more than 0.5%.
Limit of methanol and ethanol
Internal standard solution
Prepare a solution in sodium hydroxide solution (1 in 100) containing 0.7 µL of n-propyl alcohol per mL. Transfer 2.0 mL of this solution to a 250-mL volumetric flask, dilute with the same sodium hydroxide solution (1 in 100) to volume, and mix.
Standard solution
Prepare a solution in Internal standard solution containing 10.0 µg each of methanol and dehydrated alcohol per mL. Transfer 2.0 mL of this solution to a vial fitted with a septum and crimp cap, and seal. Heat the sealed vial at 90
Test solution
Transfer 40 mg of Ofloxacin, accurately weighed, to a vial fitted with a septum and a crimp cap, add 2.0 mL of Internal standard solution, and seal the vial. Heat the sealed vial at 90
Blank
Transfer 2.0 mL of the Internal standard solution to a vial fitted with a septum and crimp cap, and seal. Heat the sealed vial at 90
Chromatographic system (see Chromatography
Procedure
Use a heated gas tight syringe to make injections of the headspace into the chromatograph. Separately inject equal volumes (about 1 mL) of the headspace of the Standard solution, the Blank, and the Test solution into the chromatograph, record the chromatograms, and measure the peak area responses. Calculate the percentage of methanol and ethanol in the Ofloxacin taken by the formula:
(2/W)(RU RB)/(RS RB)
in which W is the weight, in mg, of Ofloxacin taken to prepare the Test solution; and RU, RB, and RS are the peak response ratios of the relevant alcohol peak to the internal standard peak obtained from the Test solution, the Blank, and the Standard solution, respectively: not more than 0.005% of methanol and not more than 0.05% of ethanol are found.
Assay
Transfer about 100 mg of Ofloxacin, accurately weighed, to a 400-mL beaker, add 275 mL of acetic anhydride, and stir to dissolve. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically, using a glass-silver chloride electrode system (see Titrimetry
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 4098
Pharmacopeial Forum: Volume No. 30(4) Page 1274
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