Abstract
Absorption spectra of amlodipine 4μg/ml (___) and atenolol 40μg/ml (---) using methanol as a blank. [Display omitted]
•Four spectrophotometric methods for determination of amlodipine and atenolol.•They can be used for analysis of binary mixtures with severely overlapped spectra.•They have equal accuracy, precision compared to chromatographic methods.•Ratio difference does not need fixed wavelengths or any derivative calculation.•Constant center method predicts the UV spectra of each single drug.
Four, accurate, precise, and sensitive spectrophotometric methods are developed for simultaneous determination of a binary mixture of amlodipine besylate (AM) and atenolol (AT). AM is determined at its λmax 360nm (0D), while atenolol can be determined by four different methods. Method (A) is absorption factor (AF). Method (B) is the new ratio difference method (RD) which measures the difference in amplitudes between 210 and 226nm. Method (C) is novel constant center spectrophotometric method (CC). Method (D) is mean centering of the ratio spectra (MCR) at 284nm. The methods are tested by analyzing synthetic mixtures of the cited drugs and they are applied to their commercial pharmaceutical preparation. The validity of results is assessed by applying standard addition technique. The results obtained are found to agree statistically with those obtained by official methods, showing no significant difference with respect to accuracy and precision.