Determination of Binary Mixture of Raubasine and Almitrine Dismesylate by Derivative Spectrophotometry

A first derivative spectrophotometric (D) and derivative ratio (1DD) methods were utilized to determine raubasine (I) and almitrine dismesylate respectively using methanol as a solvent. A linear relationship was obtained in the range from 6-20 μg ml raubasine for the (D) method and 1024 μg ml almitrine dismesylate for the (DD) method. By applying the proposed methods, it was possible to determine raubasine in its pure powdered from with accuracy 99.94 ± 0.860 (n = 8) for the (D) method and almitrine dismesylate with accuracy 100.07 ± 0.784 (n = 8) for the (DD) method. Laboratory prepared mixtures containing different ratios of (I), (II) were analyzed by the proposed methods. The proposed methods were validated and found to be suitable assay methods for raubasine (I) and almitrine dismesylate (II) in pharmaceutical formulations.