A rapid, sensitive method for clinical monitoring of ketamine and norketamine by ultra-high-performance reverse-phase liquid chromatography tandem mass spectrometry.
Nicholas Armfield, Bernhard Frank, Carrie Chadwick
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引用次数: 0
Abstract
Background: Ketamine is an NMDAR antagonist with aggregating use across many areas of medicine. P450 enzymes heavily metabolise ketamine, where norketamine is a first pass formed metabolite following initial N-demethylation. Serum ketamine monitoring is becoming increasingly important, requiring a sensitive method with a robust lower limit of quantitation.
Methods: Samples were prepared using protein precipitation or solid phase extraction. Ion suppression was investigated to optimise sample preparation technique, followed by reverse-phase chromatography coupled with tandem mass spectrometry to analyse extractions using a Waters Xevo TQ-S Micro and associated Acquity chromatography systems. Performance characteristics were analysed to validate the assay.
Results: Ketamine and norketamine retention times were 1.28 and 1.23 min, respectively. Ketamine and norketamine precursor ions fragmented into 2 distinguishable product ions (238.14 > 207.18/125.06 and 224.1 > 178.96/124.86). Performance characteristics include an assay recovery of 103.7% (ketamine) and 96.3% (norketamine), lower limit of quantitation 36.2 µg/L (ketamine) and 38.9 µg/L (norketamine), and intra-assay imprecision ≤ 7.04% on average.
Conclusions: A robust and reproducible assay with limited sample preparation has been designed and validated. The linearity of the assay covers all ranges of interest reported in the literature. Ion suppression was clearly reduced via use of solid phase extraction. The method will form the basis of ketamine monitoring and providing valuable patient information on tolerance and metabolism.
期刊介绍:
Annals of Clinical Biochemistry is the fully peer reviewed international journal of the Association for Clinical Biochemistry and Laboratory Medicine.
Annals of Clinical Biochemistry accepts papers that contribute to knowledge in all fields of laboratory medicine, especially those pertaining to the understanding, diagnosis and treatment of human disease. It publishes papers on clinical biochemistry, clinical audit, metabolic medicine, immunology, genetics, biotechnology, haematology, microbiology, computing and management where they have both biochemical and clinical relevance. Papers describing evaluation or implementation of commercial reagent kits or the performance of new analysers require substantial original information. Unless of exceptional interest and novelty, studies dealing with the redox status in various diseases are not generally considered within the journal''s scope. Studies documenting the association of single nucleotide polymorphisms (SNPs) with particular phenotypes will not normally be considered, given the greater strength of genome wide association studies (GWAS). Research undertaken in non-human animals will not be considered for publication in the Annals.
Annals of Clinical Biochemistry is also the official journal of NVKC (de Nederlandse Vereniging voor Klinische Chemie) and JSCC (Japan Society of Clinical Chemistry).