Objective:

The aim of this study was to develop a simple, accurate, precise method for the estimation of bupropion and dextromethorphan in a fixed dose combination of tablet and robust high performance liquid chromatography (HPLC) for assay analysis for such a fixed combination.

Materials and Methods:

Chromatographic analysis was performed and separations were achieved on a Denali C18 150 × 4.6 mm, 5 micron using mobile phase composition of orthophosphoric acid and acetonitrile in the ratio of 600:400 (v/v), the flow rate of 1.0 mL/min, injection volume is 10 μL and run time 6 minutes in isocratic elution. UV detection was carried out at a wavelength of 221 nm. The temperature was maintained at 30°C. Well-resolved peaks were observed with high number of theoretical plates, lower tailing factor and reproducible relative retention time. The method was validated and all the validation parameters were found to be within the acceptance limits.

Results:

A simple, accurate, precise method has been developed for the estimation of bupropion and dextromethorphan in a fixed dose combination of tablet. The optimized method included the following parameters: Column temperature of 30°C, 40% acetonitrile as the mobile phase and flow rate of 1.0 mL/min. Retention times were 2.25 min and 3.12 min for bupropion and dextromethorphan, respectively. The method was found to be linear in the range of 17.5-105 μg/mL (for R2 <0.999) and 7.5-45 μg/mL for (R2 >0.999) for bupropion and dextromethorphan, respectively. Both APIs were dissolved more than 90% within 5 min.

Keywords: Bupropion, dextromethorphan, stress degradation, RP-HPLC method development and validation