Enantioselective analysis of albendazole sulfoxide in cerebrospinal fluid by capillary electrophoresis

Albendazole (ABZ) is a benzimidazole anthelmintic drug used in the treatmen t of neurocysticercosis. After oral administration, ABZ is rapidly oxidized to albendazole sulfoxide (ABZSO), which has an asymmetric sulfur center, a nd later to albendazole sulfone (ABZSO(2)). ABZSO is the active metabolite responsible for the therapeutic effect of the drug. Previous studies have d emonstrated pharmacokinetic differences between the two enantiomers, with t he predominance of (+)-ABZSO in human biological fluids. This article descr ibes for the first time the enantioselective analysis of ABZSO in cerebrosp inal fluid (CSF) using capillary electrophoresis. The samples were prepared by liquid-liquid extraction using chloroform: isopropanol (8:2 v/v). The r esolution of ABZSO enantiomers was obtained with a fused-silica capillary ( 60 cm x 75 mum ID) using 20 mmol/L Tris, pH 7.0, with 3.0% w/w sulfated bet a -cyclodextrin as running buffer. The coefficient of variations and % rela tive error obtained for both within-day and between-days assays were lower than 15%. The method was linear over the concentration range of 100 to 2500 ng/mL for each enantiomer, indicating that it is suitable for the analysis of ABZSO enantiomers; in CSF from patients medicated with ABZ.