LOPINAVIR IS AN INHIBITOR OF THE HIV PROTEASE. AS CO-FORMULATED IN RITOMAX-L, RITONAVIR INHIBITS THE CYP3A-MEDIATED METABOLISM OF LOPINAVIR, THEREBY PROVIDING INCREASED PLASMA LEVELS OF LOPINAVIR. LOPINAVIR, AN INHIBITOR OF THE HIV PROTEASE, PREVENTS CLEAVAGE OF THE GAG-POL POLYPROTEIN, RESULTING IN THE PRODUCTION OF IMMATURE, NON-INFECTIOUS VIRAL PARTICLES