Ethosuximide

Absence seizure of epilepsy, as an idiopathic generalized epilepsy subtype with high incidence in childhood, has long been a therapeutic challenge in the field of pediatric neurology due to its insidious onset and high recurrence rate. Ethosuximide is a succinimide antiepileptic drug. By selectively blocking T-type calcium channels in thalamic neurons and inhibiting paroxysmal discharge of abnormal neurons, it is currently a first-line treatment for absence seizures recommended by domestic and foreign guidelines, especially suitable for children and adolescent patients with simple absence seizures. It can significantly reduce the seizure frequency, has little impact on cognitive function, and has outstanding clinical safety advantages.

The global ethosuximide market has maintained steady growth for a long time. In 2023, the market size was approximately USD 180 million, with a compound annual growth rate of around 3.2%. Due to its clear clinical positioning and relatively subdivided applicable population, the market competition pattern is relatively concentrated. The original research product accounts for more than 60% of the global market share, and the supply of generic drugs is mainly concentrated in major generic drug producing countries such as India and China. At present, the domestic market is still dominated by imported original research preparations, and the number of approved generic drugs is small. With the advancement of the security policy for children's rare disease drugs, the market demand is showing a steady upward trend.

The original research enterprise of ethosuximide is Novartis, with the original brand name Zarontin, and its core compound patent expired worldwide in 1997. The main dosage form approved for the original research product is oral capsule with a specification of 250mg. This product has been included in the FDA Reference Listed Drug Catalogue, and is also included in the *Catalogue of Reference Preparations for Chemical Drugs* of China. At present, no domestic enterprise has obtained the marketing authorization and A status registration number of ethosuximide API, nor has any domestic ethosuximide preparation been approved for marketing, so the clinical demand is completely dependent on the supply of imported original research preparations. (Data as of October 2024, please refer to the official website of CDE for the latest information)

CATO provides a full set of impurity reference standards for ethosuximide API, covering all types such as synthesis process impurities and degradation impurities. Most of the products are in stock. For in-stock products, orders placed before 16:00 will be shipped on the same day. All products meet the compliance requirements of multiple regulations such as Chinese Pharmacopoeia and FDA, and can fully meet the full-process needs of API R&D, quality research and registration declaration.