A Validated 2D-LC-UV Method for Simultaneous Determination of Imatinib and N-desmethylimatinib in Plasma and its Clinical Application for Therapeutic Drug Monitoring with GIST Patients

Background: The trough concentration (C_min ) of Imatinib (IM) is closely related to the treatment outcomes and adverse reactions of patients with gastrointestinal stromal tumors (GIST). However, the drug plasma level has great inter-and intra-individual variability, and therapeutic drug monitoring (TDM) is highly recommended. Objective: To develop a novel, simple, and economical two-dimensional liquid chromatography method with the ultraviolet detector (2D-LC-UV) for simultaneous determination of IM and its major active metabolite, N-desmethyl imatinib (NDIM) in human plasma, and then apply the method for TDM of the drug. Methods: The sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 µL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Results: IM and NDIM were separated well from other impurities and the entire analytical time for each run was 12.0 min. The calibration curves had good linearity in the range of 33.5-2678.4 ng/mL for IM, and 20.0-1600.0 ng/mL for NDIM, respectively. The extraction efficiency was more than 95%. The acceptable accuracy, precision, recovery and stability were also obtained. The C_min of the drug in patients was measured with the validated method. Conclusion: The novel 2D-LC-UV method is simple, stable, highly automated and independent of specialized technicians, which greatly increases the real-time capability of routine TDM for IM in hospital.