NMR analysis, protonation equilibria and decomposition kinetics of tolperisone

The rate constants of spontaneous and hydroxide-catalyzed decomposition and the tautomer-specific protonation constants of tolperisone, a classical muscle relaxant were determined. A solution NMR method without any separation techniques was elaborated to quantitate the progress of decomposition. All the rate and equilibrium constants were determined at four different temperatures and the activation parameters were calculated. The molecular mechanism of decomposition is proposed.