xiyanping + lopinavir + ritonavir + alpha interferon + arbidol

This formulation is a combination of five active agents: **xiyanping**, **lopinavir**, **ritonavir**, **alpha interferon**, and **arbidol**, primarily investigated for the treatment of COVID-19 and other viral respiratory infections. - **Xiyanping** is a semi-synthetic injectable preparation derived from *Andrographis paniculata*, exhibiting anti-inflammatory and antiviral properties; it is commonly used in China for upper respiratory tract infections, viral pneumonia, and hand, foot and mouth disease[3][7]. Its mechanism includes inhibition of inflammatory cytokine pathways (notably TNF signaling), and modulation of immune response[7]. - **Lopinavir** is a protease inhibitor used primarily in combination with ritonavir to enhance its pharmacokinetics; together they inhibit the **HIV-1 protease** and have been repurposed in attempts to treat SARS-CoV-2 infection[2][6]. - **Ritonavir** acts as a potent CYP3A4 inhibitor to boost the plasma levels of lopinavir, but also provides direct antiviral activity as an HIV-1 protease inhibitor[2]. - **Alpha interferon** (often administered as interferon alpha-1b) is a recombinant cytokine with broad antiviral and immunomodulatory effects, administered via injection[2][4]. It induces antiviral proteins and downregulates viral replication. - **Arbidol** (umifenovir) is a small-molecule antiviral agent that inhibits membrane fusion of enveloped viruses, including influenza and coronaviruses, thus blocking viral entry and replication[2][4]. This combination aims to provide multi-pathway antiviral, anti-inflammatory, and immunomodulatory effects in the treatment of COVID-19, and has been studied in clinical settings for its efficacy against moderate COVID-19 pneumonia, sometimes in combination or as adjunctive therapy[2][6][7].