In 1996 Youdim, in collaboration with scientists from Technion and the US National Institutes of Health, and using compounds developed with Teva Pharmaceuticals, published a paper in which the authors wrote that they were inspired by the racemic nature of deprenyl and the greater activity of one of its stereoisomers, L-deprenyl, which became selegiline, to explore the qualities of the isomers of the Aspro compound, and they found that the R-isomer had almost all the activity; this is the compound that became rasagiline. They called the mesylate salt of the R-isomer TVP-1012 and the hydrochloride salt, TVP-101.
