Stability indicating potentiometric method for the determination of palonosetron HCl using two different sensors

This paper presents a novel potentiometric approach for the determination of palonosetron HCl using two sensors; ionophore-free and ionophore-doped ones. The two sensors successfully determined the cited drug in the range of 1 × 10^-5-1 × 10^-2 M with respective Nernstian slopes of 54.9 ± 0.25 and 59.3 ± 0.16 mV/decade. Incorporating calix[8]arene as an ionophore resulted in a lower detection limit (LOD = 3.1 × 10^-6 M) and enhanced selectivity when compared to the ionophore-free sensor (LOD = 7.9 × 10^-6 M). This modification was also associated with faster response for the ionophore-doped sensor (response time = 20 s) compared to the ionophore-free one (response time = 30 s). The two sensors showed a stable response over a pH range of 3.0-8.0. They successfully determined palonosetron HCl in presence of its oxidative degradation products. They were also used for direct determination of the drug in commercially available parenteral solution without any interference from other dosage forms' additives.