Validation of densitometric and videodensitometric TLC methods for analysis of vigabatrin in pharmaceutical formulations

Abstract

Two new, simple, precise and accurate thin-layer chromatography methods with densitometric and videodensitometric detection were developed for the determination of vigabatrin in pharmaceutical preparations. The analysis was performed on silica gel 60 F₂₅₄ plates in horizontal chambers with acetone-butan-2-one-formic acid-water (40:45:5:10, v/v), as mobile phase. The method is based on the reaction of the primary amino group of vigabatrin with ninhydrin reagent producing a colored product which absorbs maximally at 483 nm. Videodensitometric assay was performed at visible light. Calibration plots were constructed in the range 2.0 - 20.0 µg/spot with good correlation coefficients r=0.9991 and r=0.9949 for densitometry and videodensitometry, respectively. The LOD was 0.6 µg and 0.8 µg per spot for densitometric and videodensitometric assay, respectively; the LOQ was 1.5 µg per spot for both methods. The active substance was extracted from tablets with methanol. The mean ± SD recovery from commercially available tablets was 100.22 ± 0.61% (n=6) for the both methods. Tablet excipients did not interfere with the chromatography. Finally, the methods were compared statistically in respect of precision and accuracy. No significant differences were observed.