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 (Cmin) 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 40C and the injection volume was 500 mu L. 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 Cmin 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.