The invention is directed to compounds that are prodrugs containing a chemical delivery system (CDS) moiety and a cysteine protease inhibitor moiety. The CDS moiety targets the prodrug to the brain or central nervous system. The cysteine protease inhibitor inhibits cysteine proteases upon release from the prodrug. Cysteine protease inhibitors are effective for treating dementia, Alzheimer's disease and vascular dementia. Targeting the brain or central nervous system offers significant advantages in treating these conditions and diseases. A preferred CDS prodrug is a dihydrotrigoneline CDS moiety coupled to an epoxysuccinyl peptide cysteine protease inhibitor moiety.
