Utility of N-bromosuccinimide as an environmental-friendly reagent for sensitive determination of olanzapine in pharmaceuticals

ABSTRACT

One titrimetric and two spectrophotometric methods are described for the determination of olanzapine [OLP] in bulk drug and dosage forms. The methods use N-bromosuccinimide [NBS] and two-dyes, namely quinoline yellow and metanil yellow, as reagents. In titrimetry, an acidified solution of OLP was titrated directly with NBS using methyl orange as indicator. Spectrophotometry involves the addition of a known excess of NBS to OLP in acid medium followed by determination of unreacted NBS by reacting with a fixed amount of either quinoline yellow and measuring the absorbance at 410 nm [method A] or metanil yellow and measuring the absorbance at 530 nm [method B]. Titrimetric method is applicable over a range of 1-10 mg of OLP, and the reaction stoichiometry is found to be 16 [OLP NBS]. In spectrophotometry, Beer's law was obeyed in the concentration ranges of 0.1-1.2 and 0.1-1.5 micro g ml[-1] OLP for method A and method B, respectively. The molar absorptivity, Sandell sensitivity, limits of detection and quantification are also reported for both the spectrophotometric methods. The proposed methods were applied successfully to the determination of OLP in tablets. The reliability and accuracy of the methods were further ascertained by recovery studies. A major advantage of the use of NBS is that the by-product succinimide can be easily recovered and recycled to NBS