(1S)-3,4-Dihydro-1-phenyl-d5-2(1H)-isoquinolinecarboxylic Acid (3R)-1-Azabicyclo-[2.2.2]oct-3-yl Ester Hydrochloride,(1S)-3,4-Dihydro-1-phenyl-d5-2(1H)-isoquinolinecarboxylic Acid (3R)-1-Azabicyclo-[2.2.2]oct-3-yl Ester Hydrochloride,Muscarinic M3 receptor antagoinst. Used in treatment of urinary incontinence. Intended for use as an internal standard for the quantification of Solifenacin by GC- or LC-mass spectrometry.,Solifenacin Stable Isotopes