Development of derivative of subtracting spectra method for the simultaneous determination of some decongestant drugs


The mixture of chlorpheniramine maleate (CPM), paracetamol (Para) and phenylephrine hydrochloride (PPH) drugs has been estimated simultaneously using a developed method. The method was simple, fast and accurate. The suggested method depends on the derivative of subtracting spectra, by subtracting the overlapping absorption spectra of two drugs out of the absorption spectra of the mixture of the three drugs to get the absorption spectrum of the third drug, then this spectrum is derived using the first and second derivative patterns, and the process was repeated for the estimating each drug. The results have exhibited, that the range of linearity was (0.1-15), (0.1-40) and (0.5-50), while the RSD% value ranged from (5.508-0.068), (1.649-0.143) and (3.744-3.744). 0.144), and RE% values (-3.542 - -0.049), (-0.958 - 0.004) and (-2.250 - 1.771), for drugs (CPM, Para and PPH) respectively. The proposed method was applied and was successfully applied for estimating drugs in some pharmaceutical forms.