Determination of three antiepileptic drugs in pharmaceutical formulations using microfluidic chips coupled with light-emitting diode induced fluorescence detection

In this study, a facile, sensitive, and precise lab-on-a-chip electrophoretic method coupled with light-emitting diode induced fluorescence (LED-IF) detection was developed to assay three antiepileptic drugs, namely, vigabatrin, pregabalin, and gabapentin, in pharmaceutical formulations. The analytes were derivatised offline for the first time with fluorescine-5-isothiocyanate (FITC) to yield highly fluorescent derivatives with lambda(ex/em) of 490/520 nm. The FITC-labelled analytes were injected, separated, and quantitated by a microfluidic electropho-resis device using fluorescence detection. The labelled analytes were monitored using a blue LED-IF system. The separation conditions were significantly optimised adding specific concentrations of heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (HDM-beta-CD) and methylcellulose to the buffer solution (40 mM borate buffer). HDM-beta-CD acted as a selective host for the studied antiepileptic drugs, rendering a high separation efficiency. Methyl-cellulose was used as an efficient dynamic coating polymer to prevent the labelled drugs from being adsorbed on the inner surfaces of the poly (methylmethacrylate) microchannels. A laboratory-prepared ternary mixture of the three antiepileptic drugs was separated within 100 s with acceptable resolution between all the three analytes (R-s > 3) and a high number of theoretical plates (N) for each analyte (N approximate to 10(6) plates/m). The sensitivity of the method was enhanced approximately 80-fold by stacking to yield a detection limit below 0.6 ng mL(-1) in the concentration range of 2.0-200.0 ng mL(-1). The method was successfully validated for analysing the studied drugs in their pharmaceutical formulations. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

A lab-on-a-chip electrophoretic method coupled with LED-induced fluorescence detection was developed for the assay of three antiepileptic drugs in pharmaceutical formulations. The method involves derivatizing analytes with FITC offline, optimizing separation conditions, and using specific compounds to enhance separation efficiency. The sensitivity of the method was greatly enhanced through stacking, allowing for successful validation in pharmaceutical formulations.