Selective Potentiometric Sensors for the Determination of Quetiapine Fumarate in Pharmaceuticals and Spiked Human Urine

Abstract

Quetiapine fumarate (QTF), chemically known as 1-[2-(2-hydroxyethoxy)-ethyl]-4-(dibenzo[b,f][1,4] thiazepin-11-yl)-piperazinium hemifumarate, is one of the derivatives of dibenzothiazepine. It is used as an atypical antipsychotic drug and is prescribed for the treatment of schizophrenia and bipolar disorders. Fabrication and the application of two selective potentiometric sensors for determination of QTF in pharmaceuticals and spiked human urine are presented. The membrane sensors are fabricated by preparing ion pair complexes of QTF with sodium tetraphenyl boron (NaTPB) and phosphotungstic acid (PTA). Using the ion-associates of QTF-NaTPB and QTF-PTA, Sensor I and Sensor II, respectively, were designed in polyvinyl chloride matrix using dibutyl phthalate as a plasticizer in THF. The fabricated Sensor I and II are applicable for the quantification QTF over the concentration range from 6.25 × 10-5 to 3.5 × 10-3 M QTF. The operative pH ranges for the determination of QTF were found to be in the range from 1.5 to 2.20 and from 1.00 to 1.6, for Sensor I and II with the Nernstian slopes of 58.34±1.04 and 57.23±0.78 mV/decade, respectively. The regression coefficient values of 0.9992 and 0.9982 show good correlation between the measured potentials and concentrations using Sensor I and II, respectively. The limit of detection (LOD) values for the fabricated sensor are calculated and reported. The experimental conditions have been optimized to reach the effective performance characteristics of the sensors. Standard-addition procedure is followed to study the effect of additives in tablets and foreign species in spiked human urine. The results revealed no such variations due to presence of additives or foreign species or endogenous species. The fabricated sensors are subjected to validation to check accuracy, precision, robustness and ruggedness. The mean accuracy for the determination of QTF is very close to 100%. The developed and validated sensors have yielded excellent results.