Abstract

Two spectrophotometric methods were validated for determination of two substances simultaneously in a binary mixture which are diosmin (DSM) and hesperidin (HSP). The first method used was the derivative spectrophotometry by the zero-crossing measurements based on the elaboration of the linear calibration graphs of first derivative values are plotted at 269 nm for HSP and 262.5 nm for DSM. The second method was the calculation of the peak absorbance ratio λmax of the two drug substances (DSM-HSP) in a binary mixture and the percentage of drugs was determined. Two different ratios were selected.
The two methods presented are simple, selective and reliable, providing satisfactory accuracy. The recoveries obtained in all cases are good and reliable agreement with the reported procedure. The results confirmed that the methods can be considered as a good alternative to other costly techniques in particular chromatographic techniques. These methods can be used easily and effectively for simultaneous dosing of two active ingredients mixed in pharmaceutical forms with precision. Also they can be used for monitoring synthesis of DSM from HSP. Given the time saved by these methods presented by the short duration of the analysis, they can be applied to routine quality control.

Key words: Spectrophotometric methods, First derivative, Simultaneous determination, Absorbance ratio.