Response surface methodology for optimization of micellar-enhanced spectrofluorimetric method for assay of foretinib in bulk powder and human urine.

This work investigates a sensitive and precise enhanced spectrofluorimetric assay for assay of foretinib (FTB); a tyrosine kinase inhibitor drug used for treatment of breast cancer, in tablets and urine through response surface optimization by micelle mediated protocol. The basis of the described method is the enhancement of the fluorescence behavior of FTB in Cremophor RH 40 (Cr RH 40) micellar medium and measuring the fluorescence of FTB at 344 nm after excitation at 245 nm. Optimization was performed through evaluation of diluting solvent, types of organized media, buffer type and its relevant pH. Response surface methodology was applied to obtain the optimized values of variables that mostly affect interaction of Cr RH 40 with FTB using Box-Behnken design. ICH guidelines were adhered for the validation of merit figures. Acceptable linear relationship was obtained between relative fluorescence intensity (RFI) and FTB concentrations in the range of 50 - 1000 µg L, with correlation coefficient of 0.998. Accuracy was ≥ 99.82% and calculated limit of detection (LOD) was 10.60 µg L. Method applications included FTB assaying in pure bulk powder. Furthermore, applications on urine samples were performed with accuracy of 100.59 ± 3.40%. The method represents echo-friendly approach and effective alternating methodology to the relevant analytical ones for FTB assaying.