Phenytoin

Abnormal electrical discharge in the central nervous system is the core pathological basis of epileptic seizures, and clinical anti-epileptic treatment has long faced the challenge of balancing seizure control and cognitive impairment reduction. Phenytoin is a hydantoin class anti-epileptic drug, which selectively blocks voltage-dependent sodium channels in neurons to inhibit the spread of high-frequency abnormal discharges. Meanwhile, it can also regulate the function of calcium channels, stabilize synaptic membranes, and reduce the release of excitatory neurotransmitters. Its indications cover generalized tonic-clonic seizures, complex partial seizures, simple partial seizures and status epilepticus. It can also be used for the treatment of trigeminal neuralgia, paroxysmal choreoathetosis and other diseases, and is one of the basic drugs for long-term management of epilepsy in adults.

The global phenytoin market size is approximately USD 320 million. Driven by factors such as stable epilepsy prevalence and expanding demand for primary care medication, the compound annual growth rate in the past five years has maintained at around 2.1%. As the drug was launched at an early stage, the global market is dominated by generic drugs, which account for more than 95% of the market share. The Chinese market is the second largest single national market in the world, with an annual sales volume of approximately RMB 470 million. Among them, oral preparations have been included in the national centralized drug procurement, and the winning bid price has dropped by more than 80% compared with the original research drug, significantly improving the accessibility at the primary level. Meanwhile, the export volume of phenytoin API produced by domestic enterprises accounts for 35% of the global production capacity, making China one of the major suppliers.

The original research enterprise of phenytoin is Pfizer, and the original brand name is Dilantin®. Its core compound patent expired globally in 1973. The main dosage forms approved for the original research product include oral tablets, injections and suspensions, with common specifications of 50mg and 100mg for tablets, and 5ml:250mg for injections. The original research product has been included in the FDA Orange Book Reference Listed Drug Catalog, and phenytoin sodium tablets and phenytoin sodium for injection marketed in China have corresponding reference listed drugs included. As of now, there are 16 registration entries of phenytoin (including phenytoin sodium) on the API registration platform of China CDE, among which 10 are in status A and can be supplied for domestic preparation production, and more than 30 enterprises have obtained approval for marketing of phenytoin-related preparations. (Data as of April 2025, please refer to the official CDE website for the latest information)

In response to the quality control requirements of phenytoin, CATO provides a full set of impurity reference standards for this API, covering all impurity types required for quality control such as synthetic intermediates and degradation products. Most of the products are in stock. For in-stock products, orders placed before 16:00 will be shipped on the same day. All reference standards comply with the compliance requirements of multiple regulatory systems such as the Chinese Pharmacopoeia and FDA, and can fully meet the quality control research needs of enterprises in the whole process of R&D, registration and production.