Abstract
tA 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 anew 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 withethyl acetate:dichloromethane (80:20, v/v). The chromatographic separation was achieved on an AscentisExpress RP-Amide column (75 mm x 2.1 mm, 2.7 m) with a gradient mobile phase consisting of 0.05 Maqueous formic acid and acetonitrile.
Detection was carried out using positive-ion electrospray tandemmass spectrometry on an LTQ XL system using the MS/MS CID (collision-induced dissociation) mode. Themethod was linear in the range 0.1-1000 ng/ml (r2= 0.999) with a lower limit of quantitation of 0.1 ng/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 accu-racy was from MINUS SIGN 7.2% to 7.4%. The method was successfully applied to a pharmacokinetic study involvingintramuscular application of 3.86 mg/kg PC 48 to rats for the first time.
Pharmacokinetic parameters forPC 48 include Cmax39.09 +- 4.45 ng/mL, Tmax5.00 +- 3.08 min, AUC0 MINUS SIGN t23374 +- 4045 min ng/mL and t1/21065 +- 246 min.