Generic Automated Fluorimetric Assay for the Quality Control of Gamma Aminobutyric Acid-Analogue Anti-Epileptic Drugs Using Sequential Injection

Abstract

The first sequential injection assay for the generic determination of gabapentin and pregabalin is reported. The analytes react with o-phthalaldehyde in the presence of N-acetylcysteine as a nucleophilic reagent in alkaline medium under flow conditions to form highly fluorescent derivatives. The effect of the main instrumental and chemical variables on the assay was examined. The proposed method was validated for both analytes in terms of linearity, detection, and quantitation limits (c _L  = 160 μg L⁻¹, c _Q  = 480 μg L⁻¹ for gabapentin, and c _L  = 70 μg L⁻¹, c _Q  = 210 μg L⁻¹ for pregabalin), precision (s _r  < 1.0% in both cases), selectivity, and accuracy. The applicability of the assay was demonstrated by successfully analyzing commercially available formulations. The experimental percent recoveries were in the range of 97.9–102.0% for gabapentin and 98.3–102.3% for pregabalin.

Keywords:

• Gabapentin
• o-phthalaldehyde
• Pregabalin
• Sequential injection
• Spectrofluorimetry

Notes

^a Three replicates per sample.

^a Three replicates per sample.