STABILITY INDICATING SPECTROPHOTOMETRIC AND TLC-DENSITOMETRIC METHODS FOR THE DETERMINATION OF ARIPIPRAZOLE IN BULK AND DOSAGE FORM

Objective: Four different methods were used for stability indicating determination of aripiprazole in presence of its oxidation product in pure and its dosage form. Methods: The described methods are namely, second derivative spectrophotometry, first-derivative of ratio spectra; bivariate and thin layer chromatography. Results: The derivative spectrophotometric method was based on measuring the peak amplitudes of second derivative spectra of aripiprazole at 217.2 and 229 nm where zero crossing points obtained with its oxidation product, over a concentration range of 1.0 – 6.0μg.ml -1 for aripiprazole. The derivative ratio spectra method was based on measuring the peak amplitudes for aripiprazole at 209.8, 222, 246.8 and 283.2 nm using 5.0μg.ml 1 oxidation product as a divisor, over a concentration range of 1.0-6.0μg.ml -1 for aripiprazole. Bivariate method is used for determination of aripiprazole in presence of oxidation product over a concentration range of 1.0 – 6.0μg.ml -1 for aripiprazole. The method was based on measuring the absorbance at the selected wavelengths. A TLC separation with densitometric detection of aripiprazole was achieved using ethyl acetate: methanol [11:4, v/v] as developing solvent. The method allowed determination of aripiprazole in concentration ranges of 1.0-4.0 μg.spot -1. Conclusion: The proposed methods are accurate, precise and successfully applied for the determination of the studied drug in presence of its oxidation product in pure form and in pharmaceutical formulations containing them, so that these methods can be used as stability indicating methods for the determination of aripiprazole in quality control laboratories.