Besifloxacin

Bacterial conjunctivitis is a common clinical ocular infectious disease. If not intervened in time, it may cause serious consequences such as corneal ulcer and visual impairment. Fluoroquinolones are the mainstream treatment option for this disease. As a fourth-generation fluoroquinolone antibacterial agent, besifloxacin blocks bacterial replication by inhibiting the activities of bacterial DNA gyrase and topoisomerase IV. It has broad-spectrum antibacterial activity against gram-positive bacteria, gram-negative bacteria and atypical pathogens, and has a particularly significant effect on staphylococcus strains resistant to other fluoroquinolones. Clinically, it is mainly used for the local treatment of bacterial conjunctivitis in adults and children over 1 year old, which can effectively shorten the time for symptom resolution and reduce the risk of disease recurrence.

The global market size of therapeutic drugs for bacterial conjunctivitis maintains a steady growth trend. In 2024, the market size has exceeded USD 3.2 billion, of which topical antibacterial drugs account for more than 60%. With the advantages of low drug resistance risk and good ocular tolerance, the market share of besifloxacin in the high-end topical antibacterial drug market is increasing year by year. At present, the original research products still occupy the main market share in the domestic market. As generic pharmaceutical companies successively make layout after the patent expiration, the accessibility of this variety will be further improved, and the demand for related research on active pharmaceutical ingredients (APIs) and impurities will also increase accordingly.

The original research enterprise of besifloxacin is Alcon, and the original trade name is Besivance. Its core compound patent in the United States expired in 2021, and the core compound patent in China expired in 2022. The main dosage form of the original research product is ophthalmic suspension, with the specification of 0.6% (3ml:18mg). This dosage form has been included in the FDA Reference Listed Drug Catalogue, and is also included in the *Catalogue of Reference Preparations of Chemical Drugs* of China. As of the retrieval time point, there is no approved and marketed registration number of besifloxacin API in China, only the original imported ophthalmic suspension has been approved for marketing, and no domestic preparation has been approved. (Data as of June 2025, please refer to the official website of CDE for the latest information)

CATO can provide a full set of impurity reference standards for besifloxacin API. The products meet the compliance requirements of multiple regulations such as the Chinese Pharmacopoeia and FDA. Most products are in regular stock. For in-stock orders, if placed before 16:00, they can be shipped on the same day, which can provide stable reference material support for the whole process of drug research and development, quality research and production quality control.