Allopregnanolone

Neurosteroids are key mediators of endogenous regulation in the central nervous system. As the most potent positive allosteric modulator among them, allopregnanolone can specifically bind to the neurosteroid binding site of the GABAA receptor, prolong the opening time of chloride ion channels, and enhance inhibitory nerve signal transduction. Its clinical applications cover multiple central nervous system disease fields such as postpartum depression, premenstrual dysphoric disorder, and status epilepticus. For patients with postpartum depression, it can rapidly improve core symptoms such as suicidal ideation and anxiety, and also serves as an emergency medication option for epileptic seizures in special populations, filling the clinical gap in rapid intervention for severe mood disorders.

Driven by the increase in the consultation rate of mental illnesses among women of childbearing age and the demand for the treatment of refractory epilepsy, the market for allopregnanolone-related preparations has maintained a rapid growth trend in recent years. In 2023, the global market size has exceeded USD 780 million, with a compound annual growth rate of over 22%. At present, the global market is still dominated by original research preparations, and there are few enterprises developing generic drugs. Only a small number of domestic pharmaceutical companies have initiated the R&D and application of generic drugs. With the awareness of postpartum depression increasing from 23% in 2019 to 47% in 2024, the domestic potential market size is expected to exceed RMB 1.2 billion within 3 years.

The original research enterprise of allopregnanolone is Sage Therapeutics, and the brand name of the original research product is Zulresso. The core compound patent in the United States will expire in 2029, and the compound patent in China will expire in 2028. The main currently approved dosage form is intravenous injection, with a specification of 100mg/20mL (5mg/mL). It has been included in the FDA Reference Listed Drug Catalog, but has not yet been included in China's *Catalog of Reference Listed Drugs for Chemical Drugs*. At present, no allopregnanolone preparation has been approved for marketing in China. There is no valid A-status registration number listed on the CDE API Registration Platform, and only 2 enterprises have submitted clinical trial applications for the API. (Data as of June 2025, please refer to the official CDE website for the latest information)

In response to the impurity research needs in the R&D process of allopregnanolone generic drugs, CATO can provide a full set of impurity reference standards for this API. Most products are in regular stock, and spot orders placed before 16:00 can be shipped on the same day. All products meet the compliance requirements of multiple regulatory systems such as the Chinese Pharmacopoeia and FDA, and can provide stable reference standard support for links such as methodological verification and stability research of pharmaceutical enterprises.