A Novel Sensor for Determination of Dexamethasone Disodium Phosphate in Different Pharmaceutical Formulations

A novel electrode was developed for potentiometric determination of dexamethasone sodium phosphate (DSP) using tetraheptyl ammonium bromide (THB) as an anionic exchanger in polyvinyl chloride (PVC) matrix and 2-nitrophenyl octyl ether (2- NPOE) as a plasticizer. Linear responses of 1×10−5 to 1×10−2 M with slope of 26.50±0.39 mV/decade within working pH range 8-12 were achieved. The percentage recovery of determination of DSP by the proposed DSP selective electrode was 99.96±0.95. Determination of DSP in its pharmaceutical formulations by the proposed electrode revealed its applicability for determination. Moreover, the electrode exhibits good selectivity for DSP with respect to a large number of interfering substances and co-formulated drugs. The fabricated sensor was validated according to ICH guidelines and successfully applied for determination of the studied drug in pure form and pharmaceutical formulations without any interference from additives either labeled or non-labeled. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official one with respect to accuracy and precision.