Determination of topiramate in dried blood spots using single-quadrupole gas chromatography-mass spectrometry after flash methylation with trimethylanilinium hydroxide.
Dried blood spots (DBS) sampling obtained from fingerpricks is a promising and patient friendly alternative for obtaining samples for drug quantification, that could be of interest for topiramate (TOP) therapeutic drug monitoring. The aim of this study was to develop and validate a simple and fast GC-MS assay for TOP measurement in dried blood spots (DBS). The method uses a liquid extraction of one 8mm DBS, followed by a flash methylation with TMAH, and separation in a DB-5ms capillary column. Total analytical run time was 15min. Precision assays presented CV% lower than 9.1% and accuracy was in the range of 94.5-115%. TOP was stable at 25 and 45°C up to 21days. TOP presents saturable binding to red blood cells, resulting in a fraction in plasma (fp) of 0.09-0.03 at 0.8μgml-1and 0.71-0.45 at 20μgml-1(both at 25-50 Hct% range). The method was applied to DBS samples obtained after phlebotomy and fingerpicks from an adult individual after oral intake of 100mg TOP (0.25-96h post dose). Plasma and DBS concentrations were moderately correlated (r=0.61), with estimated fpvalues in the range of 0.06-0.18. Translation of TOP DBS to plasma concentrations is challenging due to its concentration-dependent binding to erythrocytes. Thus, the use of whole blood concentrations for patients monitoring should be considered, which favors to the use of DBS in the clinical context.
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil.
Roberta Zilles
RZ
Hahn
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil.
Marina Venzon
MV
Antunes
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil.
Priscila
P
Costa Arnhold
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil.
Natalia Bordin
NB
Andriguetti
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil.
Simone Gasparin
SG
Verza
Graduate Program on Toxicology and Analytical Toxicology and Toxicological Analysis Laboratory, Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo-RS, Brazil. Electronic address: rafael.linden@feevale.br.
Rafael
R
Linden
D059788:Dried Blood Spot Testing / Q000379:methods*; D005632:Fructose / Q000031:analogs & derivatives* / Q000097:blood; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D016014:Linear Models; D008745:Methylation; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000077236:Topiramate
D000644:Quaternary Ammonium Compounds; D000077236:Topiramate; D005632:Fructose; C009571:phenyltrimethylammonium
Dried blood spots; Gas chromatography–mass spectrometry; Therapeutic drug monitoring; Topiramate