Potentiometric Determination of Sibutramine Using Batch and Flow Injection Analysis

Sibutramine (SBT+) ion-selective electrode (ISE) was constructed using poly(vinyl chloride) matrix membrane containing sibutramine–phosphotungstate (SBT–PTA) plasticized with dioctyl phthalate. The electrode exhibits Nernstian response of 59.54 mV/ concentration decade over the concentration range 1.0 × 10−5 to 1.0 × 10−2 M and detection limit of 7.94 × 10−6 M. The electrode was fully characterized in terms of its composition, response time, life span, pH, selectivity, and temperature and was then applied to the potentiometric determination of SBT in its pure bulk and pharmaceutical formulations under batch and flow injection conditions and for the in vitro testing of the dissolution profile of SBT capsules.