Ritonavir is an effective inhibitor of CYP3A-mediated biotransformation, and is also an effective oral inhibitor of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) aspartic proteases. Ritonavir can block the process by which this enzyme produces the polyproteins required for morphologically mature HIV particles, thereby keeping the HIV particles in an immature state, thereby slowing the spread of HIV in cells to prevent a new round Infection and delays the development of the disease.