BACKGROUND: @entity2213 (IM) is a first choice drug for treatment of @entity1860 ( @entity1860 ), with a widely accepted concentration threshold of 1000ng/ml being used as a target for therapeutic drug monitoring. Once adherence to the pharmacotherapeutic regimen is of paramount importance during the long treatment course of @entity1860 , the measurement of hair IM concentrations could be a surrogate of the @entity1 's exposure to the drug. METHODS: IM was extracted from a 5mg hair sample by a liquid-liquid extraction with @entity1046 , and IM-d8 was used as @entity3538 ( @entity3538 ). After evaporation, and reconstitution in @entity1626 , the extract was injected into a LC-MS/MS system. Compounds were eluted on a C8 column in isocratic mode. IM and @entity3538 were identified in positive electrospray ionization mode using ion transitions of m/z 494.5>394.5 and 503.0>394.3 respectively. The method was applied to 102 paired hair and samples obtained from @entity1860 @entity1 . Treatment response was evaluated according to the European LeukemiaNet recommendations. RESULTS: The assay was validated in the concentration range of 0.5-25ng/mg, with intra- and inter-assay imprecisions of <13.1% and <9.3%, respectively. The limits of quantification and detection were 0.5 and 0.15ng/mg, respectively. Median hair IM concentrations are significantly smaller in @entity1 with therapeutic failure when compared with @entity1 with partial or optimal response (4.63 vs. 7.93, p=0.040), the same trend presented by median plasma IM concentrations (629.5 vs. 1084.8, p=0.009). An IM hair concentration below 5.8ng/mg has 83% sensibility and 70% specificity to identify @entity1 with therapeutic failure. CONCLUSIONS: A fast, sensitive, and selective LC-MS/MS method allowing quantification of IM in hair samples was developed and validated. @entity1860 @entity1 with therapeutic failure had significantly lower hair IM concentrations when compared with @entity1 with optimal response. These preliminary findings may support the use of hair as a matrix for IM monitoring in clinical settings, with significant logistic advantages over the collection of venous blood, particularly in developing countries.

First report of XXXX measurement in hair: Method development and preliminary evaluation of the relation between hair and plasma concentrations with therapeutic response in @entity1860 .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity1046 :: ('MESH:C007650', 'Chemical') :: ['ethyl acetate'] @entity3538 :: ('MESH:D002341', 'Disease') :: ['IS', 'internal standard'] @entity1626 :: ('MESH:C032159', 'Chemical') :: ['acetonitrile'] @entity2213 :: ('MESH:C097613', 'Chemical') :: ['Imatinib'] @entity1860 :: ('MESH:D015464', 'Disease') :: ['CML', 'chronic myeloid leukemia']
@entity2213 :: (MESH:C097613,Chemical) :: ['imatinib']
