Exploiting steroid-cyclodextrin complexes for selective determination of Estradiol Valerate and Norethisterone Acetate by synchronous fluorescence spectrofluorimetry

Inclusion complexes of β-cyclodextrin with Estradiol valerate (EST) or Norethisterone acetate (NOR) have been utilized for synchronous fluorescence spectrofluorimetry. β-cyclodextrin improves fluorescence intensity as well as water solubility of the studied drugs. Samples in aqueous medium adjusted with ammonia were used in synchronous fluorescence to resolve the overlapped emission spectra. The effects of β-cyclodextrin concentration and Δ λ have been optimized for sensitive and selective analysis of EST and NOR binary mixture. Synchronous fluorescence intensity of the two drugs is measured at Δ λ of 70 nm. EST and NOR can be simultaneously determined at 230 nm and 270 nm, respectively. Calibration curves were linear over the ranges of 0.5-6.0 μg mL^-1 and 0.2-2.0 μg mL^-1 for EST and NOR, respectively. Official guidelines were followed to estimate the validation parameters of the proposed method. The detection limits were 0.08 μg mL^-1 for EST and 0.007 μg mL^-1 for NOR. The proposed method was successfully used for the analysis of EST and NOR in their commercial preparations and the obtained results revealed statistical agreement with those obtained by application of the reported method for both drugs. The proposed method is compared favorably to previously published method in terms of simplicity and hazardous solvent consumption.