AMIODARONE-SELECTIVE MEMBRANE-ELECTRODE

A liquid membrane electrode based on an amiodarone-dipicrylamine ion-p air complex, dissolved in nitrobenzene as solvent, is proposed for the determination of amiodarone, an antiarrhythmic drug. The linear respo nse covers the range 10(-2)-10(-5) M amiodarone solution, with a slope of 57.3 mV/decade (pH range 0.80 to 4.80). The detection limit is 4 x 10(-9) M. The electrode shows a good stability, reproducibility and f ast response. The selectivity is good against K+ and Ca2+. There are t wo strong interfering ions, ephedrine and polyvinylprolidone. The char acteristics of the electrode make it useful for the determination of a miodarone by direct and indirect potentiometric methods. Through the i ndirect potentiometric method, amiodarone can be determined as an acti ve substance with an average recovery of 99.60% and a relative standar d deviation of 0.67%, and this method can also be used for its determi nation in pharmaceutical dosage forms such as tablets and ampoules wit h a relative standard deviation less than 1%. The electrode can also b e used for dissolution tests of amiodarone tablets. The physical proce sses are numerically simulated by typical equations. The apparent firs t-order rate constants for disintegration and dissolution processes ha ve been calculated.