Development of the spectrophotometric method for the determination of atorvastatin in tablets by using bromothymol blue

The aim of the work was to develop a simple, economic, fast, reliable, and eco-friendly spectrophotometric method for the determination of atorvastatin in tablets based on the reaction with bromothymol blue (BTB). Material and methods. A double–beam Shimadzu UV-Visible spectrophotometer, with spectral bandwidth of 1 nm wavelength accuracy ±0.5 nm, Model –UV 1800 (Japan), Software UV-Probe 2.62 was used to measure absorbance of the resulting solution. Pharmacopeial standard sample of atorvastatin calcium and BTB were provided by Sigma-Aldrich (≥98 %, HPLC). The used dosage forms of atorvastatin: tablets Atorvastatin 10 mg and 20 mg. Results and discussion. The method of spectrophotometric determination of the quantitative content of atorvastatin calcium based on its reaction with BTB in ethyl acetate medium has been developed. The stoichiometric ratios of the reactive components as 1:1 were obtained by the methods of continuous changes and the saturation method. Linearity regression equation was y=0.0017x+0.0496 and the obtained correlation coefficient was R2=0.9993. The linear relationship was found between absorbance at λmax and concentration of medicine in the range 15.48–154.80 µg/mL. The LOD and LOQ values were calculated to be 4.85 µg/mL and 14.71 µg/mL respectively. Spectrophotometric method for the determination of atorvastatin in tablets using BTB was developed in accordance with GAC principles.  Conclusions. A simple, economic, fast, reliable and eco-friendly spectrophotometric method was developed for the determination of atorvastatin calcium in tablets based on the reaction with BTB and validated according to the standardized validation procedure by the standard method. It was proved that according to such validation characteristics as linearity, precision, accuracy, and robustness the proposed method met the requirements of SPhU