Ofloxacin

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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7H-Pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid, 9-uoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-, (±)-; (±)-9-Fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid CAS RN®: 82419-36- 1; UNII: A4P49JAZ9H. 

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1 DEFINITION 

Ofloxacin  contains NLT 98.0%  and NMT 102.0%  of ofloxacin  (C₁₈H₂₀FN₃O₄), calculated on the dried basis.

2 IDENTIFICATION 

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A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197A or 197K 

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B. Spectroscopic Identification Tests 〈197〉, Ultraviolet-Visible Spectroscopy

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C. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY 

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Procedure 

Diluent: Acetonitrile and water (1:6) 

Buffer: 3.1 g/L of ammonium acetate and 5.4 g/L of sodium perchlorate in water. Adjust with phosphoric acid to a pH of 2.2. Mobile phase: Acetonitrile and Buffer (570:4430) 

Standard solution: 0.2 mg/mL of USP ofloxacin  RS in Diluent 

Sample solution: 0.2 mg/mL of ofloxacin  in Diluent 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 294 nm 

Column: 4.6-mm × 15-cm; 5-μm packing L1 

Column temperature: 45° 

Flow rate: 0.5 mL/min 

Injection volume: 10 µL 

Run time: NLT 2.5 times the retention time of ofloxacin  

System suitability 

Sample: Standard solution 

Tailing factor: NMT 2.0 

Relative standard deviation: NMT 0.73% 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of ofloxacin  (C₁₈H₂₀FN₃O₄) in the portion of ofloxacin  taken:

Result = (r_U/r_S) × (C_S/C_U) × 100 

r_U = peak response of ofloxacin  from the Sample solution 

r_S = peak response of ofloxacin  from the Standard solution 

C_S = concentration of USP ofloxacin  RS in the Standard solution (mg/mL)  

C_U = concentration of ofloxacin  in the Sample solution (mg/mL) 

  Acceptance criteria: 98.0%–102.0%  on the dried basis 

4 IMPURITIES 

Residue on Ignition 〈281〉: NMT 0.1% 

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Arsenic 〈211〉, Procedures, Procedure 2  

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Organic Impurities 

Diluent, Buffer, Sample solution, and Chromatographic system: Proceed as directed in the Assay.  Mobile phase: Acetonitrile and Buffer (240:1300) 

System suitability solution: 0.4 µg/mL each of USP ofloxacin  RS and USP ofloxacin  Related Compound A RS in Diluent Sensitivity solution: 0.04 µg/mL of USP ofloxacin  RS in Diluent  

Standard solution: 0.4 µg/mL of USP ofloxacin  RS in Diluent 

  System suitability 

Samples: System suitability solution, Sensitivity solution, and Standard solution 

[Note—The relative retention times for ofloxacin  related compound A and ofloxacin  are 0.88 and 1.0, respectively.]   

Suitability requirements 

Resolution: NLT 2.0 between ofloxacin  and ofloxacin  related compound A, System suitability solution Relative standard deviation: NMT 3.0%, Standard solution 

Signal-to-noise ratio: NLT 10, Sensitivity solution  

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of each impurity in the portion of ofloxacin  taken: 

Result = (r_U/r_S) × (C_S/C_U) × 100 

r_U = peak response of each impurity  from the Sample solution

r_S = peak response of ofloxacin  from the Standard solution 

C_S = concentration of USP ofloxacin  RS in the Standard solution (mg/mL) S 

C_U = concentration of ofloxacin  in the Sample solution (mg/mL) 

Acceptance criteria: The reporting threshold is 0.02%. 

Individual impurities: NMT 0.3%  

Total impurities: NMT 0.5% 

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Limit of Methanol and Ethanol  

5 SPECIFIC TESTS 

Optical Rotation 〈781S〉, Procedures, Specific Rotation 

Sample solution: 10 mg/mL in chloroform 

Acceptance criteria: +1° to −1° 

Loss on Drying 〈731〉 

Analysis: Dry at 105° for 4 h. 

Acceptance criteria: NMT 0.2% 

6 ADDITIONAL REQUIREMENTS 

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Packaging and Storage: Preserve in well-closed containers, protected from light. Store at controlled room temperature.  Change to read: 

USP Reference Standards 〈11〉 

USP ofloxacin  RS 

USP ofloxacin  Related Compound A RS 

9-Fluoro-3-methyl-7-oxo-10-(piperazin-1-yl)-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid; 

Also known as  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. 

C₁₇H₁₈FN₃O₄347.35