A simple RP-HPLC method for related substances of zoledronic acid in pharmaceutical products

A novel, selective and sensitive reverse phase-high performance liquid chromatography (RP-HPLC) method has been developed for the validated estimation of imidazol-1-yl-acetic acid in zoledronic acid formulations. The separation was achieved on a 5 μ C18 column (250 × 4.6 mm) using a mobile phase that consists of the buffer (4.5 g of di-potassium hydrogen phosphate anhydrous and 2.0 g of tetra butyl ammonium hydrogen sulphate (TBAHS) in 1000 mL of water) and methanol in the ratio of 900:100 v/v. The flow rate was maintained at 1.0 mL min−1. The detection of the constituents was done at 215 nm using a UV detector. The retention times of imidazol-1-yl-acetic acid and zoledronic acid were 7.2 and 10.2 min respectively. Recovery studies were satisfactory and the correlation coefficient, 0.999 indicates linearity of the method within the limits. The developed method can be applicable for regular qualitative analysis.