Ritonavir is an L-valine derivative and L-valinamide in which the alpha-amino group is acylated by a [(2-isopropyl-1,3-thiazol-4-yl)methyl]methylcarbamoyl group, and the hydrogen of the carboxamide amino group is replaced by a (2R,4S,5S)-4-hydroxy-1,6-diphenyl-5-{[(1,3-thiazol-5-ylmethoxy)carbonyl]amino}hexan-2-yl group. It is a CYP3A inhibitor and antiretroviral drug from the protease inhibitor class used to treat HIV infection and AIDS, commonly administered as a fixed-dose combination with lopinavir. It is also used in combination with dasabuvir sodium hydrate, ombitasvir, and paritaprevir (as Viekira Pak) for chronic hepatitis C virus genotype 1 infection and liver cirrhosis. It functions as an antiviral drug, HIV protease inhibitor, environmental contaminant, and xenobiotic. It belongs to 1,3-thiazoles, L-valine derivatives, carbamate esters, ureas, and carboxamides.
