Lopinavir and ritonavir are commonly prescribed as a fixed-dose combination drug therapy for the treatment of Human Immunodeficiency Viruses (HIV) and belong to a class of antiviral drugs known as protease inhibitors. Lopinavir by itself has insufficient bioavailability to be an effective therapy. However, ritonavir inhibits cytochrome P450 enzymes in the liver known to break down lopinavir, increasing its concentration in the blood to its desired therapeutic window. Lopinavir and ritonavir treatment as a single medication is listed by the World Health Organization’s (WHO) list of essential medicines, which serves as a model of the safest and most effective medicines required by a health system. Early studies have shown promising results as a treatment against SARS-CoV-2 and further research is currently being conducted into its efficacy. This application brief describes the use of a Quasar C8 column for the analysis of lopinavir and ritonavir.