Arbidol hydrochloride

Arbidol Hydrochloride is a pivotal antiviral API and reference standard used extensively in the treatment of influenza A and B virus infections. As an inhibitor of viral membrane fusion, Arbidol Hydrochloride prevents viral entry into host cells, thereby blocking the initial step of infection. Beyond its direct antiviral activity, Arbidol Hydrochloride also modulates immune responses through interferon induction and macrophage activation, providing a dual mechanism of action . In quality control and pharmaceutical development contexts, Arbidol Hydrochloride reference standards are essential for analytical method development, method validation, quality control testing, and regulatory submissions. With its established efficacy and favorable safety profile, Arbidol Hydrochloride remains an important therapeutic option for influenza management.

Product Parameters

Mechanism of action

Arbidol hydrochloride can prevent the envelope of influenza virus from contacting, adhering to and fusing with the cell membrane of host cells. On the other hand, it can also induce host cells to produce interferon, and stimulate the humoral response and the phagocytosis of macrophages.

Toxicological effects

Arbidol hydrochloride has low toxicity. According to foreign literature reports, rats and guinea pigs were well tolerated after a single oral dose of 2000 mg/kg, with LD50 > 3000 mg/kg. The oral LD50 in mice is 340 mg/kg. Chronic toxicity test: No pathological changes were observed in rats given 100-125 mg/kg and dogs given 25 mg/kg orally for 6 months, and long-term administration is also safe for rabbits and guinea pigs. Both in vivo and in vitro experiments show that it has no mutagenic effect. Reproductive toxicity studies in rats show that this product has no teratogenic effect. With LD50 > 4 g/kg, administration at the recommended dose will not cause any adverse effects on the human body.

Synthetic Route

Place the reaction flask in an ice-water bath, and add 19.4 g (0.2 mol) of sulfamic acid, 40.5 mg (0.3 mol) of 30% dimethylamine aqueous solution, and 22.5 g (0.3 mol) of 37% formaldehyde aqueous solution sequentially. After slowly adding water dropwise, add 1000 mL of water, and add ethyl 6-bromo-5-hydroxy-1-methyl-2-(phenylthiomethyl)indole-3-carboxylate (84.0 g, 0.2 mol) in batches. The reaction mixture is stirred at 30°C and maintained at 40°C for 3 hours. After the reaction is completed, pour the mixture into an appropriate amount of ice water, adjust the pH to above 13 with 20% sodium hydroxide solution, cool in an ice bath, collect the solid by filtration, and wash with distilled water until neutral. Recrystallize with a mixed solvent of petroleum ether ethyl acetate to obtain the pure product. Dissolve the above pure product in acetone, control the reaction temperature at 60°C, slowly add concentrated hydrochloric acid dropwise to pH 1.0, and the dropwise addition process lasts for 30 minutes. After the dropwise addition is completed, continue the reaction for 2-3 hours, then cool and let stand. Add the obtained white product to 800 mL of 95% ethanol, stir with water (350 mL) at 25-30°C for 1-2 hours, filter after standing, and dry to obtain 91.3 g of white product (1), which is an off-white solid of arbidol hydrochloride monohydrate, with a yield of 85.6%. Confirmed by nuclear magnetic resonance (NMR) analysis, the structure of the synthesized product is consistent with that of the target product, and the purity detected by high performance liquid chromatography (HPLC) is 99.7%.

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