# A Simple Dual-Track HPLC-UV Methodology for Monitoring Primary Antiarrhythmic Drugs and Their Active Metabolites in Serum

## TL;DR

This paper introduces a cost-effective HPLC-UV method for measuring antiarrhythmic drugs and their metabolites in serum samples.

## Contribution

A new dual-track HPLC-UV methodology is proposed as an economical alternative to LC-MS/MS for drug monitoring.

## Key findings

- The method achieved reliable detection of antiarrhythmic drugs and metabolites within specified concentration ranges.
- Precision and accuracy met regulatory requirements, ensuring reliable measurements for clinical use.

## Abstract

Objectives: The aim of the work was to present a method for routine determination of antiarrhythmic drugs, propafenone (PPF), its two metabolites, 5-hydroxypropafenone (5OHPPF) and N-depropylpropafenone (NDPPF), mexiletine (MEX), amiodarone (AD) and desethylamiodarone (DEAD) in serum. Methods: A simple isocratic HPLC-UV system with a manual injector was applied. The separations were performed at ambient temperature on Supelcosil LC-CN column (150 × 4.6 mm, 5 μm). Two analytical procedures (A and B) were used: (A) for AD and (B) for PPF/MEX. The mobile phase for (A) was a mixture of: CH3OH:CH3CN:H2O:0.5M KH2PO4 (200:100:194:6 v/v + 0.1 mL 85% H3PO4 per 500 mL). The slightly acidified serum sample was extracted with hexane and the analytes were detected at 240 nm. The mobile phase for (B) was a mixture of: CH3CN:H2O:0.5M KH2PO4 (185:310:5 v/v + 0.1 mL 85% H3PO4 per 500 mL). The alkalized serum sample was extracted with diisopropyl ether, then back extracted into 0.01M HCl and finally the analytes were detected at 210 nm. Results: The method was calibrated with adequate selectivity and specificity in the range of 20–4000 ng/mL for AD, DEAD and MEX, 10–4000 ng/mL for PPF and 10–500 ng/mL for 5OHPPF and NDPPF. For all analytes, precision and accuracy fulfilled EMA requirements, i.e., ≤15% (≤20% for LLOQ), ensuring the reliability of the measurements. Conclusions: The method can be suitable for laboratories equipped with basic HPLC apparatus as an economical alternative to the LC-MS/MS technique.