Capillary electrophoresis with end-column electrochemiluminescence for ultrasensitive determination of urapidil hydrochloride in rat plasma and its application to pharmacokinetics study

A simple, sensitive and selective method for determination of urapidil hydrochloride was developed using capillary electrophoresis with electrochemiluminescence (CE-ECL) technique for the first time. Under the optimized experimental conditions, the ECL intensity was linear with the concentration of urapidil hydrochloride in the range from 0.050 to 50.0 ng/mL and the detection limit was 0.014 ng/mL (S/N = 3). The proposed method was used for studying pharmacokinetics of urapidil hydrochloride in rat plasma and the main pharmacokinetic parameters of the peak concentration (Cmax), half life time (T1/2) and peak concentration time (Tmax) were 240.45 ± 21.15 ng/mL, 0.58 ± 0.16 h and 1.08 ± 0.13 h, respectively. The recoveries of urapidil hydrochloride in the diluted extracts of rat plasma samples ranged from 96.68 to 98.82%. The RSD was lower than 3%.