Bioanalysis of EGFRm inhibitor osimertinib, and its glutathione cycle- and desmethyl metabolites by liquid chromatography-tandem mass spectrometry

Publication date: Available online 10 September 2019Source: Journal of Pharmaceutical and Biomedical AnalysisAuthor(s): J.J.M. Rood, M.J. van Haren, J.H. Beijnen, R.W. SparidansAbstractOsimertinib is a ‘‘third-generation’’ oral, irreversible, tyrosine kinase inhibitor. It is used in the treatment of non-small cellular lung carcinoma and spares wild-type EGFR. Due to its reactive nature, osimertinib is, in addition to oxidative routes, metabolized through GSH coupling and subsequent further metabolism of these conjugates. The extent of the non-oxidative metabolism of osimertinib is unknown, and methods to quantify this metabolic route have not been reported yet. To gain insight into this metabolic route, a sensitive bioanalytical assay was developed for osimertinib, the active desmethyl metabolite AZ5104, and the thio-metabolites osimertinibs glutathione, cysteinylglycine, and cysteine conjugates was developed. The ease of synthesis of these metabolites was a key-part in the development of this assay. This was done through simple one-step synthesis and subsequent LC-purification. The compounds were characterized by NMR and high-resolution mass spectrometry. Sample preparation was done by a simple protein crash with acetonitrile containing the stable isotopically labeled internal standards for osimertinib and the thio-metabolites, partial evaporation of solvents, and reconstitution in eluent, followed by UHPLC–MS/MS quantification. The assay was successfully validated...
Source: Journal of Pharmaceutical and Biomedical Analysis - Category: Drugs & Pharmacology Source Type: research