ABSTRACT

Simple and selective extractive spectrophotometric methods for the determination of quetiapine hemifumarate (QF) were developed and validated. The methods were based on the formation of yellow ion-pair complexes between QF and acidic dyes namely bromcresol purple (BCP) and bromcresol green (BCG) at room temperature in phosphate buffer (pH 3.0). The formed complexes were extracted with chloroform and the absorbances were measured at 406.5 nm for BCP and at 416 nm for BCG complexes. The compositions of the ion-pairs were found as 1:1 by mole-ratio method. The reaction conditions such as concentration, pH, color formation time, temperature and chromogen stability were optimized. Good linear relationship was obtained between the absorbance and the concentration of QF in the range of 0.5 - 20 Hg/mL for both BCP and BCG (r > 0.9974). LOD values were found as 0.12 and 0.16 \ig/mLfor BCP and BCG complexes, respectively. Intra-day precisions were found less than 1 % in the methods. The developed methods were applied successfully to the determination of QF in tablets marketed in Turkey.