Background:

Lopinavir (also known as ABT-378) is a highly potent inhibitor of human immunodeficiency virus (HIV) protease that potently inhibits wild-type and mutant HIV protease with inhibition constantK_ivalues ranging from 1.3 to 3.6 pM. Lopinavir, a ritonavir analog designed to have a diminished interaction with Val82 in HIV protease, maintains a high potency inhibiting Val82 mutant HIV selected by ritonavir with 50% effective concentration EC₅₀value lower than 0.06 μM. Although the antiviral activity of ritonavir is considerably attenuated by human serum, lopinavir is less affected by human serum proteins and is 10-fold greater in potency than ritonavir in the presence of human serum.

Reference

[1].Sham HL, Kempf DJ, Molla A, Marsh KC, Kumar GN, Chen CM, Kati W, Stewart K, Lal R, Hsu A, Betebenner D, Korneyeva M, Vasavanonda S, McDonald E, Saldivar A, Wideburg N, Chen X, Niu P, Park C, Jayanti V, Grabowski B, Granneman GR, Sun E, Japour AJ, Leonard JM, Plattner JJ, Norbeck DW. ABT-378, a highly potent inhibitor of the human immunodeficiency virus protease. Antimicrob Agents Chemother. 1998 Dec;42(12):3218-24.