# Dried Blood Spot Analysis for Simultaneous Quantification of Antiepileptic Drugs Using Liquid Chromatography–Tandem Mass Spectrometry

## TL;DR

This study shows that dried blood spots can accurately measure antiepileptic drugs, offering a less invasive and practical alternative for drug monitoring.

## Contribution

The study validates a reliable and efficient method for quantifying 11 antiepileptic drugs using dried blood spots with LC-MS/MS.

## Key findings

- An acetonitrile-based extraction method achieved high accuracy and precision for 11 antiepileptic drugs.
- All drugs remained stable in DBS samples for at least 30 days at room temperature.
- DBS results strongly correlated with whole blood concentrations, supporting DBS as a viable monitoring method.

## Abstract

Dried blood spot (DBS) sampling for the therapeutic drug monitoring of antiepileptic drugs offers practical advantages, including minimal invasiveness and ease of collection. However, for precise therapeutic management, its accuracy and reliability in quantification need to be validated.

This study validates DBS sampling for the analysis of 11 antiepileptic drugs using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS), overcoming the physicochemical challenges associated with DBS samples.

The acetonitrile‐based DBS extraction method demonstrated high efficiency for the 11 antiepileptic drugs. Accuracy and precision within 6% were achieved in both intra‐ and inter‐day assays, with good selectivity, minimal matrix effects, and negligible carryover. All antiepileptic drugs exhibited stability in DBS samples for at least 30 days at room temperature, confirming proper handling and storage of the DBS samples. A 3 mm diameter disc punched from a DBS produced accurate results for all target drugs.

The optimized method provided a time‐ and cost‐effective solution, showing a strong correlation between drug concentrations in whole blood, thereby supporting the suitability of DBS sampling as a promising and advanced method for antiepileptic drug monitoring.