Spectrofluorimetric determination of cefixime using terbium-danofloxacin probe

Objective(s):Cefixime (Cfx), is a semi-synthetic third-generation oral cephalosporin antibiotic that is prescribed for the treatment of susceptible infections. There are some procedures for the determination of Cfx in pharmaceutical formulations and biological samples. Herein a spectrofluorimetric method was proposed for Cfx determination based on the fluorescence quenching of terbium-danofloxacin (Tb۳+-Dano) in the presence of Cfx. Materials and Methods: Cfx was detected based on fluorescence quenching of terbium-danofloxacin (Tb۳+-Dano) in the presence of Cfx with maximum excitation and emission wavelengths at ۳۴۷ nm and ۵۴۵ nm, respectively. The quenched fluorescence intensity of Tb۳+- Dano system is proportional to the concentration of Cfx. The optimum conditions for the determination of Cfx were studied. Results: The maximum response was achieved under optimum conditions of [Tris buffer]= ۰.۰۰۸ mol/l (pH ۶.۵), [Tb۳+]=۱×۱۰-۴ mol/l  and [Dano]=۱×۱۰-۴ mol/l. The developed method was evaluated in terms of accuracy, precision and limit of detection. The linear concentration ranges for quantification of Cfx were ۸.۸×۱۰-۸-۸.۸×۱۰-۷ mol/l and ۱.۱×۱۰-۷-۸.۸×۱۰-۷ mol/l in standard and human serum samples with the detection limits (S/N=۳) of ۲.۸×۱۰-۸ mol/l and ۳.۹×۱۰-۸ mol/l, respectively. The Cfx was determined in pharmaceutical tablets and spiked serum samples and the results were satisfactory.   Conclusion: This method is simple, practical and relatively interference-free for determination of Cfx in pharmaceutical tablets and serum samples.

Keywords:

Cefixime , Danofloxacin , Quenching , Spectrofluorimetry , Terbium-sensitized