Development of nalbuphine-selective membrane electrode and its applications in pharmaceutical analysis

A nalbuphine ion-selective PVC membrane electrode based on ion-pair complex of nalbuphine with tetra phenyl borate was prepared with di-butyl sebacate as a plasticizer. The electrode exhibits a linear response with a Nernstain slope 59.6 mV decate(-1) at 25 degrees C with the concentration range of 1 x 10(-6)-1 x 10(-2) M nalbuphine. The electrode response was not sensitive to pH changes from 3.5-7 and not affected by possible interfering species such as common inorganic cations, sugars and aminoacids. The electrode shows good stability, reproducibility and fast response. These characteristics of the electrode enable it to be used successfully for the determination of nalbuphine hydrochloride in pure form and in pharmaceutical preparations.