Application of UV-derivative spectrophotometry for determination of some bisphosphonates drugs in pharmaceutical formulations.

A method for determination of alendronate sodium salt, clodronate disodium salt and etidronate disodium salt in pharmaceutical formulation by direct UV-spectrophotometry and/or first and second derivative UV-spectrophotometry via complex formation with Cu (II) ions is described. The calibration graphs are linear in the range 25-600 mmol/L for all the investigated compounds. No interference was found from tablet excipients at the selected wavelength and assay procedure. The developed method was validated and found to be sufficiently precise and reproducible, at least for established conditions.