DETERMINATION OF ALENDRONATE SODIUM BY ION CHROMATOGRAPHY WITH REFRACTIVE-INDEX DETECTION

Refractive index (RI) detection is applied to the ion chromatographic OC) determination of alendronate sodium, an important drug for the tre atment of bone diseases, using a Waters IC-Pak HR anion-exchange colum n with dilute nitric acid (6 mM) as the mobile phase. The method is va lidated and demonstrated to be accurate, precise, specific and robust. It is a good, alternative method for routine assay vs. the IC-indirec t UV method. The detection limit (4 . 10(-4) mg/ml) is comparable to o r better than that of the IC-indirect UV detection (1 . 10(-3) mg/ml). The mechanism of the IC separation was explored by the application of the Regnier retention model and van't Hoff analysis.