• Levofloxacin packaged and labeled.

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SKU: L001

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Levofloxacin is a broad-spectrum fluoroquinolone antibiotic, and the optical S-(-) isomer of Ofloxacin.   It is a DNA gyrase inhibitor, and has been shown to inhibit topoisomerase IV.  Levofloxacin is insoluble in aqueous solution. 

    CAS Number


    Molecular Formula

    C18H20FN3O4 • 0.5H2O

    Molecular Weight


    Mechanism of Action

    Fluoroquinolone antibiotics target bacterial DNA gyrase (specifically type II topoisomerase) an enzyme which reduces DNA strain during replication. Because DNA gyrase is required during DNA replication, subsequent DNA synthesis and ultimately cell division is inhibited.  It has also been shown to inhibit topoisomerase IV. 

    Storage Conditions


    Tariff Code



    Levofloxacin is a broad-spectrum antibiotic targeting most aerobic Gram-positive and Gram-negative bacteria.  It is moderately active against anaerobes.  It can also be used against Mycoplasmas.   It is effective against pathogens causing pneumonia such as  Streptococcus pneumoniae, and Haemophilus influenzae.



    Levofloxacin can be used in pharmacokinetic studies and to research antibiotic resistance mechanisms.

    Microbiology Applications

    Levofloxacin is commonly used in clinical in vitromicrobiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram -positive and Gram-negative microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options.  Representative MIC values include:

    • Haemophilus influenzae 0.00625 µg/mL – 1 µg/mL
    • Streptococcus pneumoniae 0.05 µg/mL - 4 µg/mL
    • For a complete list of Levofloxacin MIC values, click here.





    Light yellow crystalline powder



    Impurity Profile

    Impurity A| (-)-(S)-9-Fluoro-2,3-dihydro-3-methyl-10-(1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid; N-Desmethyl Levofloxacin|117707-40-1|C17H18FN3O4|347.34| Impurity B| 8,9-Difluoro-3-methyl-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid; Levofloxacin Difluoro Carboxylic Acid|100986-89-8|C13H9F2NO4|281.21| Impurity C| Ethyl (S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylate ; Levofloxacin Ethyl Ester|177472-30-9|C20H24FN3O4|389.42| Impurity D||||| Impurity UN1| LEVOFLOXACIN N-OXIDE ; (-)-(S)-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 N-oxide||C18H20FN3O5|377.37| Levofloxacin R-Isomer| (+)-(R)-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; (R)-(+)-Ofloxacin; D-Ofloxacin; D-Levofloxacin|100986-86-5|C18H20FN3O4|361.37| Levofloxacin Desethylene Impurity| N,N*-Desethylene Levofloxacin Hydrochloride; (-)-(S)-9-Fluoro-2,3-dihydro-3-methyl-10-[(2-methylamino)ethylamino]-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine||C16H19ClFN3O4|371.79| Levofloxacin Descarboxy Impurity| (-)-(S)-9-Fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine|178964-53-9|C17H20FN3O2|317.36| Levofloxacin Desethylene Diformyl Impurity| Desethylene Diformyl Levofloxacin; N,N*-Desethylene-N,N*-diformyl Levofloxacin; (S)-9-Fluoro-10-[formyl[2-(formylmethylamino)ethyl]amino]-2,3-dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid|151377-74-1|C18H18FN3O6|391.35| Levofloxacin Desfluoro Impurity| (-)-(S)-2,3-Dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid|117620-85-6|C18H21N3O4|343.38|

    Melting Point

    218-227 °C

    Optical Rotation

    -95° to -103°


    (As is): Not less than 98.5%

    Loss on Drying

    Not more than 3.0%

    Residue On Ignition

    Not more than 0.2%

    Heavy Metals

    Not more than 20 ppm



    Bebear CM, Renaudin H, Bryskier A, Bebear C (2000) Comparative activities of telithromycin (HMR 3647), levofloxacin, and other Antimicrobial Agents against human Mycoplasmas . Antimicrob. Agents and Chemother.  44 (7) 1980-1982  PMID  10858366

    Davis R and Bryson HM (1994)  Levofloxacin. A review of its antibacterial activity, pharmacokinetics and therapeutic efficacy. Drugs. 47(4):677-700  PMID 7516863

    Wolfson JS and Hooper DC (1985)  The fluoroquinolones: Structures, mechanisms of action and resistance, and spectra of activity in vitro. Antimicrob. Agents Chemother.  28(4):581-586  PMID  3000292

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