Diflunisal

In the long-term management of chronic pain in the musculoskeletal system such as osteoarthritis and rheumatoid arthritis, non-steroidal anti-inflammatory drugs are among the core medications for clinical symptom relief. As a salicylic acid derivative NSAID, diflunisal reduces prostaglandin synthesis through reversible inhibition of cyclooxygenase activity, with both anti-inflammatory and analgesic dual effects. Compared with aspirin, it has milder gastrointestinal adverse reactions and longer duration of action. It is mainly used to relieve mild to moderate pain, and can also be used as a symptomatic treatment option for patients with osteoarthritis and rheumatoid arthritis. It is suitable for adult patients who require long-term control of inflammatory pain, and can maintain stable plasma drug concentration without frequent administration.

The global market size of diflunisal is stable at around USD 320 million, of which generic drugs account for more than 90%. As the world's main supplier of diflunisal API, China's production capacity accounts for 68% of the global total production capacity. In the past three years, the annual compound growth rate of domestic API exports has reached 7.3%, and the products are mainly sold to North America, Europe and Southeast Asian markets. The domestic preparation side has been included in the provincial centralized procurement catalog, and the winning bid price has dropped by 47% compared with that before the centralized procurement, which promotes the further concentration of API demand to compliant leading production capacity.

The original research enterprise of diflunisal is Merck & Co., Inc., with the original research brand name Dolobid. Its core compound patent in the United States expired in 1994, and the compound patent in China has expired. The main dosage forms approved by the original research are tablets, with specifications including 250mg and 500mg. Both the 250mg and 500mg tablets have been included in the FDA Reference Listed Drug Catalog, and are also included in China's *Catalog of Reference Preparations for Chemical Drugs (8th Batch)*. As of now, there are 6 diflunisal API registration records on China CDE API Registration Platform, among which 3 are in status A and can be officially associated with preparation declaration. A number of domestic enterprises have obtained approval for the marketing of diflunisal tablets. (Data as of June 2025, please refer to the official CDE website for the latest information)

CATO provides a full set of impurity reference standards for diflunisal API. Most of the products are in stock. For in-stock products, orders placed before 16:00 will be shipped on the same day. They fully comply with the compliance requirements of multiple regulations including the Chinese Pharmacopoeia and FDA, and can fully meet the reference standard use requirements in various stages of API R&D, quality research and declaration.