Simultaneous determination of two amino bisphosphonates drugs by micellar electrokinetic chromatography

A sensitive micellar electrokinetic chromatographic method with laser-induced fluorescence detection was developed for the determination of alendronate sodium (ALN) and pamidronate disodium (PAM) after derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole. The developed method was first used for the determination of ALN and PAM in pharmaceutical preparations. After optimization, baseline separation of the analytes could be obtained in <10 min in a running buffer composed of 10 mM sodium borate and 30 mM sodium dodecyl sulfate (pH 9.0) at a voltage of 15 kV with 25°C cartridge temperature and the samples were injected by pressure (3447.5 Pa × 3 s). The method has linearity range of 0.05-70 µg/mL for the analytes (correlation coefficients: 0.9995 and 0.9997), the detection limits were 4 and 10 ng/mL for ALN and PAM, respectively. In intraday precision experiment, the relative standard deviation (RSD) values for migration time were 0.30% (ALN) and 0.27% (PAM), and the RSD values for peak areas were 1.19% (ALN) and 1.32% (PAM). The ranges of recovery were 95.5-101.8 and 94.6-105.3% for ALN and PAM, respectively. This method is not only rapid and accurate but also has the potential to be used for the quality control in pharmaceutical preparations of the two drugs.