Simultaneous determination of clodronate and its partial ester derivatives by ion-pair reversed-phase high-performance liquid chromatography coupled with evaporative light-scattering detection.

A new ion-pair HPLC method coupled with evaporative light-scattering detection (ELSD) for the simultaneous determination of clodronate and its partial esters has been developed. The simultaneous chromatographic separation was achieved on a reversed-phase C8 column with a gradient system and butylamine as an ion-pair reagent. This method provides good enough reproducibility and sensitivity for in vitro determinations of clodronate and its ester derivatives. The method is applied for hydrolysis studies of clodronate monoesters which have been described as possible prodrugs of clodronate.