Development and validation of a simple method for the determination of Atorvastatin calcium in pure and pharmaceutical formulations using spectrofluorimetry

A simple, accurate, precise, sensitive and selective spectrofluorimetric method was developed and validated for the determination of Atorvastatin calcium (ATV), an HMG-CoA reductase inhibitor, in its pure and tablet dosage form. The proposed method was based on direct measurement of the native fluorescence of ATV. Fluorescence analysis was accomplished by using an emission wavelength 385 nm after excitation at the wavelength of 270 nm in acetonitrile, without difficult preparation steps of the sample solution such as separation, extraction, pH adjustment or derivatization. All variables affecting the fluorescence intensity such as measurement time, temperature, and diluting solvent were investigated and optimized. Under the typical conditions, a validation study for linearity, range, accuracy, precision, selectivity and robustness of the proposed method was implemented according to ICH guidelines. The fluorescence intensity was linear over concentration range of (0.4–12) μg/ml (r = 0.9999), and the lower limits of detection and quantification were 0.079 and 0.24 μg/ml, respectively. Good accuracy and precision results were obtained through using the presented method with excellent mean recovery value 100.08 ± 0.32 which was in the acceptable range (98.0–102.0%), and RSD <2%, proving the precision of the developed method. Specificity was proved in the presence of excipients and Amlodipine besylate (AML) which encountered usually as combined drug with ATV. The developed method was successfully applied to the analysis of pharmaceuticals containing the mentioned drug with no interference from other drugs or dosage form additives, and the recoveries were in the range of 99.11 ± 0.75 to 100.89 ± 0.70. Furthermore, the obtained results were compared with reported HPLC method. Then, the t- and F- values were calculated and compared with the theoretical ones, which indicate good precision and high accuracy of the proposed method. Therefore, this method is valuable, reliable, and very suitable to be applied in routine quality control laboratories.