CRITICAL REVIEW ON THE ANALYTICAL METHODS FOR THE DETERMINATION OF ZWITTERIONIC ANTIEPILEPTIC DRUGS-VIGABATRIN, PREGABALIN, AND GABAPENTIN-IN BULK AND FORMULATIONS

Drugs with antiepileptic activity constitute a group of heterogeneous compounds and therefore their determination cannot follow a universal procedure. Among them, vigabatrin, pregabalin, and gabapentin are of similar nature, due to their zwitterionic structure. This structure enables similar approaches for their determination, including derivatization protocols. This article presents a thorough survey on published methods for the determination of this subgroup of antiepileptic compounds in bulk and pharmaceutical preparations. Spectrophotometric and spectrofluorimetric methods, with or without derivatization reagents, as thin-layer chromatography, high-performance liquid chromatography with various detectors, gas chromatography, capillary electrophoresis, infrared, and potentiometric methods, have been extensively applied for these compounds, providing reliable results. Additionally, the number of citations and purpose for each method were discussed with critical commentary.