A novel spectrophotometric three point detection method for estimation of montelukast sodium and bilastine individually as well as simultaneously in bulk drug, aqueous samples and formulations

Abstract

Montelukast sodium and bilastine have been approved in fixed dose combination of 10 mg and 20 mg, respectively, by CDSCO for treatment of allergic rhinitis in adults. Quantitative estimation of drugs is of vital importance during various stages of drug development. Simultaneous estimation of such drugs is a concern as these interact with each other during estimation. Bilastine was not found to interact montelukast sodium at its absorption maximum i.e. 344 nm whereas montelukast sodium was found to interact bilastine throughout UV range. So, montelukast sodium has been simply evaluated at 344 nm as single standard while developing a novel method for estimation of bilastine simultaneously nullifying the interaction of montelukast sodium. The calibration graphs for montelukast sodium and bilastine are linear over concentration ranges of 6-40 μg/mL and 4-40 μg/mL, respectively. As per ICH Q2 (R1) guidelines, both the curves have been found to be specific, precise, accurate, robust and rugged as indicated by the results of validation parameters within specified limits. Also, the method neither requires any complex equipment nor specific software. The calibration curves, thus formed, are useful to evaluate the respective drug alone and in the mixtures/ samples of these two drugs in combination.