RESUMO
Two simple, precise and accurate first derivative spectrophotometric methods were developed for the determination of Zolpidem Tartrate in pharmaceutical formulations in phosphate buffer pH 6.8 and acetate buffer pH 4.0. Beer’s law was obeyed over the concentration range 0.5-20 μg/ml in both phosphate buffer (pH 6.8) (Method A) and acetate buffer (pH 4.0) (Method B). The regression equations were found to be y = 0.101x+0.012 (r2 = 0.999) and y = 0.064x+0.009 (r2 = 0.999) in Method A and B respectively. The % RSD in precision studies was found to be 0.28-0.69 (Intra-day) and 0.31-0.73 (Inter-day) for Method A and 0.25-0.82 (Intra-day) and 0.26-0.57 (Inter-day) for Method B respectively. The % RSD in accuracy studies was also found to be 0.14-0.19 (Method A) and 0.18-0.23 (Method B) with percentage recovery 98.67-99.78 and 98.56-99.83 Method A and B respectively.