SPECTROFLUORIMETRIC DETERMINATION AND OPTIMIZATION OF FLURALANER IN PHARMACEUTICAL FORMULATIONS

A sensitive and accurate native spectrofluorimetric method was developed and validated for the quantification of Fluralaner in pharmaceutical formulations. Fluralaner exhibited native fluorescence with emission detected at 333 nm following excitation at 265 nm. Method optimization involved evaluating the effects of various solvents, pH levels, and buffer volumes on fluorescence intensity. Methanol, combined with 0.1 N hydrochloric acid at pH = 1, was determined to be the optimal medium for maximizing fluorescence intensity. The method demonstrated excellent linearity in the concentration range of 1–5 µg/mL, with a determination coefficient (r²) of 0.999. The limits of detection (LOD) and quantitation (LOQ) were calculated to be 0.181 µg/mL and 0.548 µg/mL, respectively. Precision and accuracy were confirmed through intra-day and inter-day studies, with relative standard deviations (RSD) less than 2% and recoveries ranging from 98.5% to 99.5%. The validated method was successfully applied to the analysis of Fluralaner in commercially available Bravecto® chewable tablets. The results showed good agreement with the label claim, with a recovery of 99.2 ± 1.1%. The proposed method demonstrates simplicity, robustness, and suitability for routine quality control analysis of Fluralaner in pharmaceutical preparations. This spectrofluorimetric approach offers a valuable alternative to more complex chromatographic techniques for the quantification of Fluralaner in drug formulations.