Physico-chemical properties and stabilities of a new positive inotropic agent, 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl] -2(1H)-quinolinone (OPC-8212).

3,4-Dihydro-6-[4-(3,4- dimethoxybenzoyl )-1-piperazinyl]-2(1H)- qu inolinone ( OPC -8212), a new positive inotropic agent, was examined to clarify its physico-chemical properties, i.e. elemental analysis, melting point, spectra (UV, IR, NMR, MS), X-ray diffraction pattern, thermal analysis, solubilities, pKa, partition coefficient and chromatography (HPLC, TLC). Some degradation products of OPC -8212 were identified in acidic and basis solutions. OPC -8212 was determined by nonaqueous titration.