Mzik_2016_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1020_85

A simple, rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative determination in rat plasma of a new candidate for AD treatment, namely PC 48 (a 7-MEOTA-donepezil like compound) in rat plasma. Sample preparation involved pH adjustment with sodium hydroxide followed by solvent extraction with ethyl acetate:dichloromethane (80:20, v/v). The chromatographic separation was achieved on an Ascentis Express RP-Amide column (75mmx2.1mm, 2.7mum) with a gradient mobile phase consisting of 0.05M aqueous formic acid and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry on an LTQ XL system using the MS/MS CID (collision-induced dissociation) mode. The method was linear in the range 0.1-1000ng/ml (r2=0.999) with a lower limit of quantitation of 0.1ng/mL. Extraction recovery was in the range 63.5-72.1% for PC 48 and 70.5% for reserpine (internal standard, IS). Intra- and inter-day precisions measured as relative standard deviation were below 10.8% and accuracy was from -7.2% to 7.4%. The method was successfully applied to a pharmacokinetic study involving intramuscular application of 3.86mg/kg PC 48 to rats for the first time. Pharmacokinetic parameters for PC 48 include Cmax 39.09+/-4.45ng/mL,Tmax 5.00+/-3.08min, AUC0-t 23374+/-4045minng/mL and t1/2 1065+/-246min.