Zoledronate and Related Impurities Analysis by Capillary Zone Electrophoresis

A capillary zone electrophoretic (CZE) method has been developed for the determination of zoledronate and its related impurities (phosphyte and phosphate). Successful separation of the drug from the impurities was achieved using 7.5 mM of phthalic acid adjusted to pH 3.50 with TRIS, as background electrolyte with an indirect detection at 205 nm. The optimized method was validated for specificity, precision, linearity and accuracy. The limit of detection was 1.8 μg ml-1 and the limit of quantification was 5.9 μg ml-1 for phosphyte. The limit of detection was 2.8 μg ml-1 and the limit of quantification was 9.3 μg ml-1 for phosphate. The developed CZE method used to determine zoledronate, phosphyte and phosphate as bisphosphonates impurities can be used to evaluate the quality of regular production samples of zoledronate.