Forty-nine monoamine oxidase inhibitor (MAOI)-related patents published between January 1998 and July 2002 are included in this review. They are classified and reviewed under three categories: (i) novel chemical entities, (ii) novel formulations, delivery systems and processing methods of known MAOIs and (iii) novel utilities and/or pharmaceutical compositions of known MAOIs. All novel compounds patented during this time were designed based on pharmacophores of known MAOIs: indoles, tricyclic heterocyclics, phenylethylamines, aminoindans, aliphatic propargylamines, tetrahydroisoquinolines, phenyloxazolidinones, and amidines. Among them, a series of indole and aminoindan derivatives were designed to contain dual pharmacophores and inhibit both monoamine oxidase (MAO) and cholinesterase (ChE). A series of MAOI prodrugs, designed to be activated by MAOs, were also claimed. Novel drug delivery systems are claimed in the patents of the second category. The most notable of these are the transdermal therapeutic systems for the application of desoxypeganine and befloxatone. The majority of the issued patents belong to the third category and are by definition less innovative. These patents explored new and/or known therapeutic utilities of new formulations and/or pharmaceutical compositions of known MAOIs.
