A simple high-throughput method for determination of antiepileptic analogues of γ-aminobutyric acid in pharmaceutical...

Pregabalin (PGB), gabapentin (GBP), and vigabatrin (VGB) are structural analogues of γ-aminobutyric acid used for the treatment of different forms of epilepsy. Their analytical determination is challenging since these molecules have no significant UV or visible absorption. Several derivatization methods have been developed and used for their determination in bulk or pharmaceutical dosage forms. We aimed to develop a high- throughput method using a microplate reader with fluorescence detection and simple derivatization with fluorescamine. Obtained method involves derivatization step of only 5 min at room temperature and simultaneous measurements of 96 samples (λex 395, λem 476 nm) thus rendering excellent high-throughput analysis. The method was found to be linear with r²>0.998 across investigated analytical ranges of 0.75 to 30.0 µg/mL for PGB, 2.00 to 80.0 µg/mL for GBP, and 1.50 to 60.0 µg/mL for VGB. Intraday and interday precision values did not exceed 4.93%. The accuracy was ranging between 96.6 to 103.5%. The method was also found to be specific since used excipients did not interfere with the method. The robustness study showed that derivatization procedure is more robust than spectrofluorimetric conditions. The developed high-throughput method was successfully applied for determination of drug content and dissolution profiles in pharmaceutical dosage forms of studied antiepileptic drugs.