Abstract: Objective To develop a method for the determination of reboxetine mesilate in plasma by high performance liquid chromatography.Methods With maprotiline hydrochloride as the internal standard,1 mL plasma sample was extracted with 5 mL distilled diethyl ether and re-extracted with 0.2 mol·L^-1 HCl 0.2 mL.The HCl phase was evaporated to dryness with N₂ stream at 80 ℃～100 ℃,and the residues were dissolved with 50 μL mobile phase.The compounds were separated on an Inertsil ODS-3 column(GL Sciences,5 μm,4.6 mm×150 mm).The mobile phase was composed of acetonitrile-50 mmol/L sodium phosphate(pH=6)(40∶60,v/v) and vacuum filtered with 0.45 μmol/L micro filtration film.The flow rate of mobile phase was 0.6 mL·min^-1.The UV detection wave length was 210 nm.Results The relationship of the peak height ratio of reboxetine mesilate to maprotiline vs.reboxetine mesilate concentration in plasma was linear within the range of 3.12～200 ng·mL^-1,r = 0.999 7.The lowest detection limit was 0.5 ng and the lowest concentration detected was 2 ng·mL^-1.The extraction recovery of reboxetine mesilate was 82.50%～86.08%.The within-and between-batch precisions were 2.02%～5.33% and 3.83%～8.50%,respectively.Conclusion The method is sensitive,precise,reproducible and specific,and can be used in the pharmacological research and therapeutic monitoring of reboxetine mesilate.

Key words: reboxetine mesilate, plasma concentration, HPLC, UV detection