Determination of eletriptan in plasma and saliva using automated sequential trace enrichment of dialysate and high-performance liquid chromatography.

The use of the system, automated sequential trace enrichment of dialysates (ASTED), to prepare plasma and saliva prior to high pressure liquid chromatography of eletriptan (HPLC) is described. Chromatographic identification of one metabolite, UK-135,800 was also established. Using this technique the procedure was observed to be specific and linear over the range 0.50-250 ng/ml. The intra-batch imprecision (C.V.) of the method ranged from 0.56 to 5.70% at plasma eletriptan concentrations from 5.00 to 200 ng/ml, and the corresponding inter-batch imprecision ranged from 1.44 to 6.36%. At these plasma analyte concentrations, the overall inaccuracy (% bias) of the procedure ranged from -5.00 to 1.50%. Similar performances were observed for the estimation of eletriptan in saliva using near identical assay conditions. The application of the assay to a pharmacokinetic investigation during a clinical study is presented.