Ritonavir

Ritonavir is an HIV protease inhibitor.¹ It inhibits recombinant HIV-1 protease by 79% when used at a concentration of 0.5 nM. It inhibits HIV-1_3B-induced cell death in MT-4 human T cell leukemia cells (EC₅₀ = 25 nM) as well as cell death induced by HIV-1_LAI, HIV-2_ROD, and HIV-2_EHO in human MT-2 cells (IC₅₀s = 0.045, 0.13, and 0.24 μM, respectively).^1,2 Ritonavir also inhibits the cytochrome P450 (CYP) isoform CYP3A (IC₅₀ = 0.14 μM).³ It inhibits CYP-mediated oxidative metabolism of the HIV protease inhibitors saquinavir (Item No. 9001893), indinavir (Item No. 15150), nelfinavir (Item No. 15144), and amprenavir (Item No. 15369) in rat and human liver microsomes in a concentration-dependent manner.⁴ Ritonavir (10 mg/kg) also prevents decreases in plasma levels of these four compounds in rats. Formulations containing ritonavir have been used in the treatment of HIV-1 infection.

WARNING This product is not for human or veterinary use.

1. Kempf, D.J., Shan, H.L., Marsh, K.C., et al. Discovery of ritonavir, a potent inhibitor of HIV protease with high oral bioavailability and clinical efficacy. J. Med. Chem. 41(4), 602-617 (1998).

2. Koh, Y., Nakata, H., Maeda, K., et al. Novel bis-tetrahydrofuranylurethane-containing nonpeptidic protease inhibitor (PI) UIC-94017 (TMC114) with potent activity against multi-PI-resistant human immunodeficiency virus in vitro. Antimicrob. Agents Chemother. 47(10), 3123-3129 (2003).

3. Kumar, G.N., Dykstra, J., Roberts, E.M., et al. Potent inhibition of the cytochrome P-450 3A-mediated human liver microsomal metabolism of a novel HIV protease inhibitor by ritonavir: A positive drug-drug interaction. Drug Metab. Dispos. 27(8), 902-908 (1999).

4. Kempf, D.J., Marsh, K.C., Kumar, G., et al. Pharmacokinetic enhancement of inhibitors of the human immunodeficiency virus protease by coadministration with ritonavir. Antimicrob. Agents Chemother. 41(3), 654-660 (1997).