Investigation on the effect of different factors such as silver nanoparticles on the luminescence of drug-terbium complex for developing of an analytical method for quantification of drugs

Abstract

Introduction: Terbium-sensitized fluorescence is one of the simple and sensitive methods for quantification of drugs in different samples. Silver nanoparticles can enhance the intensity of terbium-sensitized fluorescence and provide a more sensitive method. Silibinin is a natural flavonoid with potent anticancer properties shown in both in vitro and in vivo experiments. Enrofloxacin is one of the common antibiotics and the determination of its residue in animal products is recommended because of healthy problem for human. Aims: The present work is aimed at providing a simple analytical method for the quantitative determination of silibinin and enrofloxacin in different samples based on the formation of a fluorescent complex with terbium ion. Methods: Various parameters affecting the fluorescence intensity i.e. terbium and silver nanoparticles concentration, pH and volume of buffer were optimized using response surface methodology. Then, the optimized parameters were applied to validation of method for silibinin and enrofloxacin quantification in different samples. Results: Under the optimum conditions for determination of silibinin, the method provided a linear range between 0.10 to 0.50 mg/L with a coefficient of determination (R2) of 0.997. The limit of detection and limit of quantification (LOD and LOQ) were 0.034 mg/L and 0.112 mg/L, respectively. The linearity of method for determination of enrofloxacin was between 0.050 to 0.60 mg/L and limit of detection (LOD) and limit of quantification (LOQ) of method were 0.021 mg/L and 0.069 mg/L, respectively. Conclusion: These results made the developed method a simple, low cost and suitable analytical approach for the quantification of silibinin in aqueous solution and plasma samples and enrofloxacin determination in bovine milk.