Mianserin Hydrochloride, also known as Mianserin HCl, carries CAS No. 21535-47-7, molecular formula C18H21ClN2 and molecular weight of 300.83. It is an off-white to pale yellow solid pharmaceutical small molecule with a decomposing melting point over 230°C and a flash point of 9°C. This compound has a water solubility of 3.4 mg/mL and is also soluble in ethanol, methanol and DMF, requiring cold storage at 2–8°C for stable preservation. As a serotonin antagonist antidepressant raw material, we supply high-purity reagent-grade Mianserin Hydrochloride, alongside deuterated analog Mianserin D3, reference standards, related impurities and synthetic intermediates. Complete supporting technical materials including MSDS, synthetic routes and pharmacological research data are provided, catering to laboratory testing, central nervous system drug screening and antidepressant pharmaceutical R&D projects.