Consumer group Essential Inventions petitioned the NIH to override the Norvir patent, but the NIH announced on August 4, 2004, that it lacked the legal right to allow generic production of Norvir. Research
In 2020, the fixed-dose combination of lopinavir/ritonavir was found not to work in severe COVID-19. In the trial the medication was started around thirteen days after the start of symptoms. Virtual screening of the 1930 FDA-approved drugs followed by molecular dynamics analysis predicted ritonavir blocks the binding of the SARS-CoV-2 spike (S) protein to the human angiotensin-converting enzyme-2 (hACE2) receptor, which is critical for the virus entry into human cells. References
Further reading
Chemburkar SR, Bauer J, Deming K, Spiwek H, Patel K, Morris J,  et al. (2000). "Dealing with the Impact of Ritonavir Polymorphs on the Late Stages of Bulk Drug Process Development". Organic Process Research & Development. 4 (5): 413–417. doi:10.1021/op000023y. External links
"Ritonavir". Drug Information Portal. U.S. National Library of Medicine.
Aspergillus, Candida, Cryptococcus, Mucorales, Coccidioides, Histoplasma capsulatum, Blastomyces dermatitidis, Bipolaris, Exophiala dermatitidis, Curvularia pallescens, Ochroconis gallopava, Ramichloridium mackenziei, Pseudallescheria boydii), Protozoa (e.g. Toxoplasma gondii, Entamoeba histolytica, Trypanosoma cruzi, Schistosoma, Paragonimus), and Helminths (e.g. Taenia solium). Organisms that are most frequently associated with brain abscess in patients with AIDS are poliovirus, Toxoplasma gondii, and Cryptococcus neoformans, though in infection with the latter organism, symptoms of meningitis generally predominate.These organisms are associated with certain predisposing conditions:

Sinus and dental infections—Aerobic and anaerobic streptococci, anaerobic gram-negative bacilli (e.g. Prevotella, Porphyromonas, Bacteroides), Fusobacterium, S. aureus, and Enterobacteriaceae
Penetrating trauma—S. aureus, aerobic streptococci, Enterobacteriaceae, and Clostridium spp. Pulmonary infections—Aerobic and anaerobic streptococci, anaerobic gram-negative bacilli (e.g. Prevotella, Porphyromonas, Bacteroides), Fusobacterium, Actinomyces, and Nocardia
Congenital heart disease—Aerobic and microaerophilic streptococci, and S. aureus
HIV infection—T. gondii, Mycobacterium, Nocardia, Cryptococcus, and Listeria monocytogenes
Transplantation—Aspergillus, Candida, Cryptococcus, Mucorales, Nocardia, and T. gondii
Neutropenia—Aerobic gram-negative bacilli, Aspergillus, Candida, and Mucorales

Diagnosis
The diagnosis is established by a computed tomography (CT) (with contrast) examination. At the initial phase of the inflammation (which is referred to as cerebritis), the immature lesion does not have a capsule and it may be difficult to distinguish it from other space-occupying lesions or infarcts of the brain. Within 4–5 days the inflammation and the concomitant dead brain tissue are surrounded with a capsule, which gives the lesion the famous ring-enhancing lesion appearance on CT examination with contrast (since intravenously applied contrast material can not pass through the capsule, it is collected around the lesion and looks as a ring surrounding the relatively dark lesion).