Detection of Bisphosphonates in Equine Urine and Plasma with Liquid Chromatography-Mass Spectrometry and its Application to an Administration Study of Tiludronic Acid in the Horse

摘要

A LC/SRM method was developed for the screening of bisphosphonates in horse urine and plasma. Bisphosphonates are hydrophilic drugs that are difficult to extract from biological matrices and are poorly retained in reversed phase columns. We have overcome these problems by employing a mixed-mode weak anion exchange solid phase extraction and by methylation of the bisphosphonates with trimethylsilyldiazomethane prior to LC/SRM analysis. The developed method has a fast instrumental turnaround time, acceptable precision and recovery, and negligible interference from sample matrices. The applicability of the method was demonstrated by using it to analyse tiludronic acid post-administration samples.