Inhibitor of prolyl endopeptidase, a serine peptidase that may be implicated in the biosynthesis of amyloid β-peptide. Potently inhibits rat brain prolyl endopeptidase (Ki = 0.95 nM) in vitro, and prevents amyloid β-peptide deposition in vivo. Orally active and brain penetrant. Purity 96%. MW (observed): 508.69