First derivative spectroscopic method for simultaneous estimation of mesalazine and rifaximin in synthetic mixture

Objective: The present study was aimed to describe a simple, sensitive, rapid, accurate, precise and economical first derivative spectrophotometric method for the simultaneous determination of Mesalazine (MESA) and Rifaximin (RIFA) in synthetic mixture. Methods: The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first order derivative spectra were obtained in 0.01 N NaOH and the determinations were made at 329.20 nm (ZCP of RIFA) for MESA and 292.80 nm (ZCP of MESA) for RIFA. The linearity was obtained in the concentration range of succinate 10-50 μg/ml for MESA and 10-50 μg/ml for RIFA. Results: The limit of determination was 0.321 μg/ml and 0.301 μg/ml for MESA and RIFA, respectively. The limit of quantification was 0.974 μg/ml and 0.912 μg/ml for MESA and RIFA, respectively. The mean recovery was 100.20 and 99.52% for MESA and RIFA, respectively. The method was found to be simple, sensitive, accurate and precise and was applicable for the simultaneous determination of MESA and RIFA in synthetic mixture. The results of analysis have been validated statistically and by recovery studies. Conclusions: The method was successfully applied to pharmaceutical synthetic mixture which is considered in approved patent which show no interference. The result of analysis has been validated statistically and by recovery studies. So, this method accurate, precise, robust, rugged and economic in nature.