Difluprednate

Ocular inflammation and allergy-related diseases have long troubled patients with dry eye disease and postoperative inflammation, and this population is in urgent need of topical medication regimens with strong anti-inflammatory effects and low systemic side effects. As a topical glucocorticoid active pharmaceutical ingredient (API), difluprednate belongs to the corticosteroid receptor agonist. It exerts potent anti-inflammatory and anti-allergic effects by inhibiting the synthesis and release of inflammatory mediators and reducing capillary permeability. It is mainly used clinically for the preparation of ophthalmic topical preparations to treat ocular surface inflammation caused by dry eye disease, inflammatory reactions after ophthalmic surgery, and ocular diseases such as allergic conjunctivitis. Due to the extremely low systemic absorption after topical administration, it is suitable for patients with ocular diseases who require long-term local anti-inflammatory treatment.

The current global market size of difluprednate is approximately USD 210 million. Driven by the year-on-year increase in the prevalence of dry eye disease and the steady growth in the volume of ophthalmic surgeries, the compound annual growth rate (CAGR) in the past three years has maintained at 7.2%. At present, the market supply is dominated by the original research enterprise and a small number of compliant generic pharmaceutical companies, with the United States and the European Union being the major consumer markets. With the release of demand for ophthalmic medications in China, the growth rate of market demand for this API has exceeded 11%. Due to the high threshold for generic development after the expiration of the original research patent, the number of API suppliers that have passed the associated review in China is still small at present, and the gap between market supply and demand remains relatively obvious.

The original research enterprise of difluprednate is Bausch & Lomb Incorporated (U.S.), with the original brand name Durezol. Its core compound patent in the United States expired in 2024, and the compound patent in China has expired. The main dosage forms approved for the original product are ophthalmic ointment and 0.05% ophthalmic emulsion. Among them, the 0.05% ophthalmic emulsion has been included in the FDA Reference Listed Drug (RLD) Catalog, and is also included in the *Catalogue of Reference Preparations for Chemical Drugs (5th Batch)* of China. At present, the difluprednate APIs of 2 domestic enterprises have completed registration with the Center for Drug Evaluation (CDE) with the status of A (available for use in marketed drugs), and another 3 domestic difluprednate ophthalmic emulsion products have been approved for marketing by the National Medical Products Administration (NMPA). (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 difluprednate, covering all types required for research including process impurities and degradation impurities. Most of the products are kept in stock. Spot orders placed before 16:00 can be shipped on the same day. All products meet the regulatory requirements of multiple regions such as the Chinese Pharmacopoeia and FDA, and can provide stable support of impurity reference standards for the R&D, quality research and declaration processes of APIs.