Kinetic and maximum-absorbance spectrophotometric methods for the determination of olanzapine

Two simple and sensitive spectrophotometric methods were developed for the determination of olanzapine (OLZ) based on its oxidation with potassium iodate in a sulfuric acid medium to produce an intense violet-colored species exhibiting a maximum absorbance at 537 nm. The initial rate of formation and the maximum absorbance of the violet-colored oxidized product were monitored, in the first and second methods. The various experimental parameters affecting the rate of development and stability of the oxidized product were carefully studied and optimized. Beer’s law was obeyed up to 4.0 and 7.0 μg cm⁻³ OLZ with correlation coefficients of 0.998 and 0.996 (n = 6) and detection limits of 0.1 and 0.15 μg cm⁻³, for the initial rate and maximum absorbance methods. The proposed methods were conveniently applied to the determination of OLZ in its dosage forms and in spiked serum samples.