Ozenoxacin is a synthetic, non-fluorinated quinolone antibacterial active pharmaceutical ingredient used primarily in topical dermatological formulations. It is a modern quinolone antimicrobial with activity against important Gram-positive skin pathogens and is particularly associated with the treatment of impetigo. The FDA identifies Ozenoxacin as a quinolone antimicrobial, while PubChem classifies it among antibacterial agents and topoisomerase inhibitors.
Ozenoxacin has the molecular formula C₂₁H₂₁N₃O₃, molecular weight 363.42 g/mol, and CAS Number 245765-41-7. The chemical identity is independently confirmed by the FDA Substance Registration System, PubChem and the USP reference-standard listing.
Ozenoxacin is structurally related to the quinolone class but is notable for being a non-fluorinated quinolone. Its chemical structure contains a quinolone-3-carboxylic acid core, a cyclopropyl group, methyl substituents and a substituted pyridinyl group containing a methylamino functionality.
The systematic chemical name is:
1-Cyclopropyl-8-methyl-7-[5-methyl-6-(methylamino)pyridin-3-yl]-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
The USP reference standard identifies Ozenoxacin with CAS 245765-41-7, molecular formula C₂₁H₂₁N₃O₃, and molecular weight 363.41 g/mol; USP's monograph preview rounds the molecular weight to 363.42 g/mol.
Ozenoxacin is a quinolone antimicrobial. Its antibacterial activity is associated with inhibition of bacterial DNA replication through interference with bacterial DNA gyrase and topoisomerase IV.
The compound is particularly relevant to Gram-positive skin pathogens. Its topical application provides localized antibacterial activity with very low systemic exposure. PubChem notes that systemic exposure following topical administration is negligible.
Ozenoxacin is principally used as a topical antibacterial API. In the United States, the FDA approved Ozenoxacin 1% cream for topical treatment of impetigo caused by susceptible Staphylococcus aureus or Streptococcus pyogenes in patients aged 2 months and older.
Pharmaceutical applications include:
Recent pharmaceutical research has also evaluated Ozenoxacin in nano-emulsion and nano-emulgel systems, with reverse-phase HPLC used for analytical characterization.
Ozenoxacin inhibits bacterial enzymes involved in DNA replication. Like other quinolone antibacterials, it targets bacterial DNA gyrase and topoisomerase IV, thereby interfering with DNA replication and bacterial growth.
Its non-fluorinated chemical structure differentiates it structurally from many earlier fluoroquinolone antibiotics. This characteristic is relevant when Ozenoxacin is compared with conventional fluoroquinolone APIs.
A particularly important development for API documentation is the USP Ozenoxacin monograph proposal. USP's current public preview states that there was no existing USP monograph for the drug substance and that a new monograph based on validated analytical methods has been proposed. The proposed assay and organic-impurity procedures use liquid chromatography with an XTerra RP18/L1 column, with a typical Ozenoxacin retention time of approximately 11 minutes.
USP also describes Ozenoxacin as a white to pale-yellow crystalline powder, soluble in DMSO and soluble in water at pH 8.5.
This is important for your CMS because the USP page is currently a monograph proposal/preview, rather than evidence that a finalized USP monograph with all numerical acceptance criteria is already official. Therefore, numerical release limits should not be falsely presented as finalized USP requirements.
Liquid chromatography is an important analytical method for Ozenoxacin. USP's proposed monograph specifically states that both the Assay and Organic Impurities procedures are based on validated liquid-chromatographic methods. The proposed method uses an XTerra RP18 column with L1 packing, and the typical retention time of Ozenoxacin is about 11 minutes.
USP has also established reference standards for Ozenoxacin, Ozenoxacin Related Compound A, and Ozenoxacin Related Compound B, indicating the importance of chromatographic impurity control for this API.
Related-substance control is particularly important for Ozenoxacin because USP has established specific reference standards for Related Compounds A and B. The USP proposal indicates that organic impurities are controlled using validated liquid chromatography.
For CMS purposes, it is preferable to use the exact impurity limits from the approved/current API specification or finalized pharmacopoeial monograph rather than converting a research-grade purity value into a regulatory specification.
Ozenoxacin is described by USP as a white to pale-yellow crystalline powder. USP's public monograph preview states that it is soluble in DMSO and in water at pH 8.5.
Commercial reference specifications can report higher purity values such as ≥99.0% or 99.9%, but those values are supplier/reference-product specifications and should not automatically be described as official USP requirements. One currently listed commercial specification reports 99.0–101.0% on the anhydrous basis, LOD NMT 2.0%, heavy metals NMT 10 ppm, water NMT 1.0%, sulfated ash NMT 0.5%, total impurities NMT 0.5%, and individual unspecified impurity NMT 0.10%.
For the USP Ozenoxacin reference standard, the listed storage temperature is 2–8°C.
For bulk pharmaceutical API, the final storage condition should follow the approved stability data, packaging specification and manufacturer's validated storage requirements.
Ozenoxacin API manufacturing requires controlled chemical synthesis, purification and analytical characterization. Quality control should cover identity, assay, related substances, residual solvents, water/LOD, inorganic residue and other applicable pharmaceutical quality attributes.
For an API product page, the correct chemical identity is:
Ozenoxacin — CAS 245765-41-7 — C₂₁H₂₁N₃O₃ — molecular weight 363.42 g/mol.
Ozenoxacin is particularly relevant for manufacturers developing topical antibacterial products, including creams and other dermatological dosage forms. Its established topical use in impetigo and its quinolone antibacterial mechanism make it an important specialized dermatological API.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 99.0–101.0% on anhydrous basis |
| Loss on Drying | NMT 2.0% |
| Residue on Ignition | NMT 0.1% |
| Heavy Metals | NMT 10 ppm |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 0.5% |
| Water Content | NMT 1.0% |