Validation and Comparison of Two Analytical Methods for Imatinib Therapeutic Drug Monitoring

Abstract

Objective: Our objective was to validate and compare the automated and chromatography methods for determining imatinib levels in plasma, in terms of linearity, precision, accuracy and specificity, for therapeutic drug monitoring. Methods: Imatinib patterns were prepared in human plasma and were analysed by both methods to determine the calibration curve of each method. The methods were validated for linearity, extraction recovery, intra- and inter-day precision (relative standard deviation, RSD%), accuracy, and specificity of imatinib analysis. Method comparison study was carried out using the imatinib concentrations determined in the 25 patient samples by Deming regression and Bland–Altman analysis. Results: The calibration curve of the automated and chromatography methods were linear over the range 500–2750 ng/ml (r = 0.996) and 500–3000 ng/ml (r = 0.999), respectively. Intra- and inter-day precision showed that not all the CV values of the drug were below 15% for the automated method, recommended by the EMA and the FDA. In contrast, all CV values for precision of the chromatography method are below 6.0%. Average recovery percentage is 94.4% and 100.8 for the automated and chromatography methods, respectively. Agreement between the two methods was illustrated using Bland–Altman plot with a mean difference (Immunoassay—UPLC-UV) of 191.28 ng/ml and a 95% confidence interval of − 201.41 to 583.97 ng/ml. Deming regression analysis showed that the correlation coefficient for the automated method versus the chromatography method was 0.927 Conclusions: The chromatographic technique was the better option for therapeutic drug monitoring of imatinib in clinical practice in patients with Chronic Myeloid Leukemia (CML).