Novel Spectrophotometric Methods for Simultaneous Determination of Rosuvastatin Calcium, Timolol Maleate and Diclofenac Sodium in Pharmaceutical Ternary Mixture and Spiked Human Plasma

Three sensitive, times saving, precise and accurate spectrophotometric techniques have been established and confirmed for the simultaneous determination of ternary admixture of rosuvastatin calcium (ROSCa), timolol maleate (TIM) and diclofenac sodium (DICNa). Method A, first derivative of ratio spectra spectrophotometric (1st DD) which is the most simple simplest one. Using the spectrum of an aliquot of 5 μg/mL of DICNa as a divisor, ROSCa could be determined by measuring 1DD amplitudes at 239.5 and 266.5 nm for ROSCa, while TIM could be similarly determined at 307.7 and 331 nm. DICNa could be determined at 269.7 and 292 nm when 5 μg/mL aliquot of ROSCa was used as a divisor without interference. This method showed limit of detection of 0.556, 0.567 & 0.3 µg/mL and correlation coefficients of 0.9997, 0.9998 and 0.9995 for ROSCa, DICNa and TIM respectively. Method B, depends on subjecting the ratio spectra to mean centering (MCRS). The arithmetical description of this method was explained. The method was performed for the estimation of these drugs together in one run without preseparation in authentic laboratory prepared mixtures, bulk and spiked human plasma. The wave lengths 277.9, 313.1 and 333.12 nm were used for the quantitative estimation of each of the studied drugs with good correlation coefficients (0.9998, 0.997& 0.9999 and LOD of 0.297, 0.150 & 0.24 µg/mL for the studied drugs in the previously mentioned order. Method C, successive-ratio derivative spectra method (SRDS). The mathematical description of the method was explained. By using this method, ROSCa, TIM and DICNa could be determined at 264, 339 and 300 nm, respectively. Correlation coefficients were 0.9998, 0.9999 & 0.9995 and LOD values of 0.374, 0.258 & 0.769 µg/mL in the same order. The three methods were linear in the range 5-25 µg/mL. The obtained results has been statistically compared with those obtained by the published one, showing no significant difference regarding accuracy and precision at p = 0.05. The developed methods do not need sophisticated techniques or instruments, besides being sensitive, selective and eco-friendly.