Osalmid (Oxaphenamide) is a choleretic drug, inhibits ribonucleotide reductase activity by targeting ribonucleotide reductase small subunit M2 (RRM2).

RRM2:8.23 μM

Osalmid 被鉴定为潜在的核糖核苷酸还原酶小亚基M2（RRM2）抑制剂。Osalmid 在抑制核糖核苷酸还原酶（RR）活性方面较羟基脲活跃10倍。Osalmid 以时间和剂量依赖性的方式抑制HepG2.2.15细胞中HBV DNA及cccDNA的合成。Osalmid对HBV DNA抑制的EC50分别为培养上清的11.1 μM和和用药8天后的16.5 μM。Osalmid 能浓度依赖性地抑制RR活性，IC50为8.23 μM。研究还表明，Osalmid对3TC耐药HBV株具有强效活性，暗示了其治疗耐药HBV感染的潜力[1]。

Osalmid 减少 RR 活性和 HBV 转基因小鼠中 HBV 的复制，并与 3TC 显示出协同效应。每日经口给予 400 mg/kg 的 Osalmid 以时间依赖的方式引起对 HBV DNA 复制的抑制。于治疗 4 周后的对照组相比，Osalmid 可在小鼠血清和肝组织中抑制 HBV DNA 复制约 40-45%[1]。

HepG2.2.15 cells are cultured in the presence of 200 μg/mL G418. Cell viability is determined using a Cell Counting Kit-8 in 96-well plates treated with Osalmid for designated times. For long term assays, the culture supernatants are replaced with fresh media containing Osalmid every two days. The control wells contained equivalent amounts of DMSO. The CC50 is calculated as the concentration of a compound that reduced the cell viability to 50% compared to the control[1].