Quantitative determination of albendazole metabolites in sheep spermatozoa and seminal plasma by liquid chromatographic analysis with fluorescence detection

A new analytical method for the simultaneous quantitative determination of albendazole metabolites in sheep spermatozoa and seminal plasma at levels down to 46.5 ng/mL for albendazole sulphoxide (ABZ-SO), 7.5 ng/mL for albendazole sulphone (ABZ-SO 2) and 12 ng/mL for albendazole 2-aminosulphone (ABZ-SO 2NH 2) has been developed. Analytes were extracted from alkalinized samples with ethyl acetate. Separation was carried out on a C 18 column in the presence of tetra -n-butylammonium (TBA) hydrogen sulphate and octanesulphonate sodium (OCT), as ion-pair agents. Fluorometric detection was performed with excitation and emission wavelengths set at 290 and 320 nm, respectively. Accuracy data showed overall recoveries (±S.E.M.) of 83.1±1.2% for ABZ-SO, 98.8±0.6% for ABZ-SO 2 and 85.3±0.7% for ABZ-SO 2NH 2, in spermatozoa. Respective values in seminal plasma were 88.0±0.9%, 97.7±0.5% and 93.2±1.7%. Precision data suggested coefficient of variation (CV%) values lower than 5.9% for spermatozoa and 3.8% for seminal plasma. The method was successfully applied for the determination of the three albendazole metabolites in semen samples collected from rams that had been orally administered albendazole.