Application of capillary zone electrophoresis with indirect UV detection to the determination of a model drug, vigabatrin, in dosage forms.
OBJECTIVE
Vigabatrin, an anti-epileptic drug with poor UV absorptivity, is used as a model drug to investigate parameters affecting quantitative determination of cationic drugs using capillary zone electrophoresis with indirect UV detection.


METHODS
All experiments were performed on a HP 3D CE instrument equipped with an on-column diode array UV absorbance detector. Untreated fused silica capillaries with an inner diameter of 50 microm, an outer diameter of 365 microm, and a total length of 50 cm (41.5 cm to the detector) were used. Indirect UV detection was performed at 214 nm. Operational parameters such as buffer type and concentration, its pH, probe type and concentration, and the impact of co-ions on the efficiency of separation, were studied. Sabrilex sachets and Sabril tablets were subjected to analysis in this study.


RESULTS
Optimal separation and quantification of vigabatrin was obtained using 5 mM sodium phosphate buffer containing 5 mM benzyl tri-ethyl ammonium hydroxide (BTEA) at pH 2.2, with 8-aminocaprylic acid as the internal standard. The method was linear over a range of 5-150 microg/ml (r = 0.9911) and a wider range of 100-600 microg/ml (r = 0.9937) concentration of the drug. The relative standard deviation (RSD) of migration time for 10 consecutive injections of a standard solution of vigabatrin was 0.19%. The limit of quantification (LOQ) was 5 microg/ml.


CONCLUSIONS
The method was demonstrated for quantification of vigabatrin in both tablet and sachet dosage forms and proved to be a very specific and fast (8 min) means of routine analysis of the drug in dosage forms, in assay or dissolution testing.
Shafaati
Alireza
A
Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada. ashafaati@yahoo.com
Lucy
Charles
C
D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004304:Dosage Forms; D019075:Electrophoresis, Capillary / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D020888:Vigabatrin / Q000032:analysis* / Q000737:chemistry*
D004304:Dosage Forms; D020888:Vigabatrin