Abbott Laboratories (now, via spinoff,
Abbvie) was one of the earliest users of the
Advanced Photon Source (APS), a national synchrotron-radiation light source at
Argonne National Laboratory. One of the early research projects undertaken at the APS focused on proteins from the human immunodeficiency virus (HIV). Using the APS beam line for
X-ray crystallography, researchers determined viral protein structures that allowed them to determine their approach to the development of HIV protease inhibitors, a key enzyme target that processes HIV polyproteins after infection, the function of which allows the lifecycle of the virus to proceed. As a result of this
structure-based drug design approach using the Argonne APS, Abbott was able to develop new products that inhibit the protease, and therefore stop virus replication. Administered alone, lopinavir has insufficient
bioavailability; however, like several HIV protease inhibitors, its blood levels are greatly increased by low doses of ritonavir, a potent inhibitor of intestinal and hepatic
cytochrome P450 3A4, which would otherwise reduce drug levels through
catabolism. and in the European Union in March 2001. In March 2020, during the
COVID-19 pandemic, the
Israeli government announced that it would force AbbVie to license its patents for lopinavir/ritonavir. In response, AbbVie announced that it would cease enforcing its patents on the drug entirely. ==Society and culture==