Determination of donepezil hydrochloride in human and rat plasma, blood and brain microdialysates by HPLC with a short C30 column

A simple and sensitive HPLC method with fluorescence (FL) detection for determination of donepezil (DP) in plasma and microdialysate samples was developed. A rapid isocratic separation of DP could be achieved by a short C30 column using mobile phases of 25 mM citric acid/50 mM Na2HPO4 (pH 6.0)–CH3CN (73:27%, v/v) containing 3.5 mM sodium 1-octanesulfonate for plasma and H2O–CH3CN–CH3OH (80:17:3%, v/v/v) containing 0.01% acetic acid for microdialysate. The eluate was monitored at 390 nm with an excitation at 325 nm. The detection limits (S/N = 3) of DP for human plasma, rat plasma and rat brain or blood microdialysates were 0.2, 1.0 and 2.1 ng/ml, respectively. Reproducible results could be obtained by using (±)-2-[(1-benzyl-piperidine-4-yl)ethyl]-5,6-dimethoxyindan-1-one hydrochloride as an internal standard (IS).The method was successfully applied for monitoring of DP levels in rat plasma, blood and brain microdialysates and patient plasma.