Rapid analysis of alkylphosphonate drugs by capillary zone electrophoresis using indirect ultraviolet detection

A rapid capillary electrophoretic method for the analysis of three alkylphosphonate drugs (i.e. fosfomycin disodium (FOS), clodronate disodium (CLO) and alendronate sodium (ALN)) was developed by using multiple probe BGE and indirect UV detection. BGE containing 30 mM benzoic acid, 5 mM salicylic acid and 0.5 mM CTAB (pH 3.8), temperature of 30°1C, applied voltage of -30 kV and detection at 220 nm provided baseline separation of all analytes (resolution (R)>2.2) in 3.2 min. EOF reversal by addition of CTAB and negative voltage polarity leading to the co-EOF flow and short analysis time. Two probe BGE greatly improved peak symmetry. The method showed good linearity (r²>0.999 in ranges of 20-1000 μg/mL for FOS, 100-1000 μg/mL for CLO and 100-750 μg/mL for ALN) repeatablitiy (RSD<2.15%), recovery (99.3-101.1%) and sensitivity (LOD<50 μg/mL). Freshly prepared BGE and sample solutions are essential for the method precision and accuracy. This new method can be utilized for routine analysis of FOS, CLO and ALN in dosage forms because of its efficiency, reliability, speed and simplicity.