Development and validation of an LC–MS/MS method for relevant drugs in epilepsy patients using dried blood spots

Abstract

Epilepsy is one of the most common diseases of the central nervous system globally. To ensure the correct dosage of antiepileptic treatment, it is helpful to check the blood levels of the administered substances regularly. The analysis of the capillary dried blood samples provides a promising and less‐invasive alternative to venous blood collection. Therefore, the aim of the present study was to develop an LC–MS method for the quantification of 22 commonly used drugs in patients with an epileptic syndrome and 5 drug metabolites in one dried blood spot (DBS). The calibration ranges were selected in such a way that the therapeutic reference ranges in serum for the respective substances were completely covered. The analytical validation was successfully performed according to relevant guidelines with a consideration of requirements for DBS analysis. Proof of concept of the developed method was obtained by the analysis of DBSs from 282 authentic leftover ethylenediaminetetraacetic acid blood samples, which were compared with the corresponding serum concentrations. Altogether, the results show a dependency on the blood/plasma (b/p) ratios of the respective analytes so that for drugs with b/p ratios close to one, for example, lacosamide, levetiracetam, brivaracetam, and sertraline, a good accordance was observed.

Dried blood spot analysis with liquid chromatography and mass spectrometry: Trends in clinical chemistry

“…With MS, the exact mass of the analyte is determined, often followed by a fragmentation of the analyte, and finally mass determination of these fragments. The monitoring of such reactions allows for highly confident identifications compared to other common detection LC-MS/MS analysis of antiepileptic drugs, LC-MS/MS analysis of clenbuterol [22,33] devices, such as those based on UV-spectroscopy. Furthermore, measurements can be performed in untargeted mode (e.g., data-dependent or data-independent acquisition [DIA]), or targeted mode, that is, choosing analytes on beforehand to maximize sensitivity (e.g., selected reaction monitoring = SRM or multiple reaction monitoring [MRM]).…”

“…For the analysis of small molecules (e.g., drugs and metabolites), the DBS or punch is typically extracted with organic solvents such as methanol or acetonitrile during shaking at room temperature or controlled heating. The extract can be dried (using e.g., nitrogen) and reconstituted in a suitable solvent, for example, the mobile phase, or injected directly, with or without centrifugation and/or filtration steps [17][18][19][20][21][22]. In contrast to the common approach of organic solvent extraction for small molecules, Gjelstad and co-workers investigated biopolymer-based cards, made of alginate and chitosan foams.…”

An LC-MS/MS Method for Quantification of Lamotrigine and Its Main Metabolite in Dried Blood Spots

“…Till present, several analytical methods have been reported for the analysis of LTG and/or its main metabolite in plasma or serum samples [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] as well as in dried blood [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]; however, there were no methods for the determination of lamotrigine together with its main metabolite in DBS. We consider the latter highly valuable for identifying the reasons for the changed LTG clearance in patients with sub- or supra-therapeutic plasma levels.…”

“…Our objective was to develop and validate an LC-MS/MS method for the determination of LTG and its main metabolite, LTG-N2-GLU, in DBS samples according to the current guidelines and recommendations for DBS assays [ 40 , 41 ]. In this study, we present a successful validation and application of the developed method for the determination of whole blood concentrations of both analytes in patients with epilepsy on stable LTG therapy.…”

Comprehensive characterization of amino acids and water‐soluble vitamins in a pentylenetetrazole‐induced seizures rat model

“…LC-MS-based targeted metabolomics is a very powerful approach that could detect dozens even hundreds of small molecules in bio-samples simultaneously [18][19][20], and this technique has been more and more applied to fundamental and clinical research of various diseases including epilepsy [21]. Dan Bylund and colleagues developed an HPLC-MS/MS method for the analysis of amino acids in a mixed mode [22].…”