Capillary electrophoresis-electrochemiluminescence detection method for the analysis of ibandronate in drug formulations and human urine.

A simple, rapid and sensitive CE method coupled with electrochemiluminescence (ECL) detection for direct analysis of ibandronate (IBAN) has been developed. Using a buffer solution of 20 mM sodium phosphate (pH 9.0) and a voltage of 13.5 kV, separation of IBAN in a 30-cm length capillary was achieved in 3 min. ECL detection was performed with an indium tin oxide working electrode bias at 1.6 V (versus a Pt wire reference) in a 200-mM sodium phosphate buffer (pH 8.0) containing 3.5 mM Ru(bpy)(3)(2+) (where bpy=2,2'-bipyridyl). Derivatization of IBAN prior to CE-ECL analysis was not needed. Linear correlation (r=0.9992, n=7) between ECL intensity and analyte concentration was obtained in the range of 0.25-50 μM IBAN. The LOD of IBAN in water was 0.08 μM. The developed method was applied to the analysis of IBAN in a drug formulation and human urine sample. SPE using magnetic Fe(3)O(4)@Al(2)O(3) nanoparticles as the extraction phase was employed to pretreat the urine sample before CE-ECL analysis. The linear range was 0.2-12.0 μM IBAN in human urine (r=0.9974, n=6). The LOD of IBAN in urine was 0.06 μM. Total analysis time including sample preparation was <1 h.