A development of LC–MS method combining ultrafiltration and lyophilization for determination of r-RGD-Hirudin in human serum

A reliable and validated LC–MS method was established for determination of r-RGD-Hirudin in human serum. Ultrafiltration was used instead of liquid–liquid extraction or solid phase extraction for water solubility drug r-RGD-Hirudin extraction. Freeze drying was used for concentration. The experiment conditions, including pre-processing procedure and LC–MS, have been investigated and optimized. Comparing with reported assays, the current method showed significant improvement in specificity, linearity, precision and sensitivity. This method has been successfully applied in clinical research of r-RGD-Hirudin.