DIFFERENTIAL-PULSE POLAROGRAPHIC-DETERMINATION OF OXYIMINO)-1-AZABICYCLO[2.2.2]OCTANE-3-ACETONITRILE MONOHYDROCHLORIDE IN TABLETS FOLLOWINGDERIVATIZATION WITH DIMETHYLDIOXIRANE

Dimethyldioxirane was used as a derivatizing agent to convert xyimino) -1-azabicyclo[2.2.2]-octane-3-acetonitrile monohydrochloride (I) to th e corresponding quinuclidine N-oxide which was then determined by diff erential pulse polarography in the presence of common excipients, The polarographic method yielded an LOD of 1.2 mu g ml(-1) calculated from the linearity plot by conventional statistical means, However, by inc reasing the pulse amplitude to 100 mV, a 5.0 ng ml(-1) solution could be detected, This constituted an approximate eight-fold improvement ov er conventional HPLC procedures, The method was suitable for dosage fo rms containing I at levels as low as 100 ppm, Samples were extracted w ith phosphate buffer solution of pH 7.0, diluted into Britton Robinson buffer solution of pH 3.0 and the polarographic response recorded at a peak potential of -0.97 V. The method was linear over the sample con centration range of 0.05 to 25 mu g ml(-1) with r = 0.9993. The precis ion for the determination of I at the 100 ppm level was 0.5%.