Analysis and pharmacokinetics studies of gastrodin and p-hydroxybenzyl alcohol in dogs using ultra fast liquid chromatography–tandem mass spectrometry method

A simple, sensitive and reliable ultra fast liquid chromatography-electrospray ionization-tandem mass spectrometry (UFLC-ESI-MS/MS) method was developed for simultaneously quantifying gastrodin (p-hydroxy-methyl-phenol-β-d-glucoside) and its metabolite p-hydroxybenzyl alcohol (HBA) in dog plasma. Separation was performed on an ultra fast liquid chromatography (UFLC) system. Detection was carried out on a tandem mass spectrometry (MS/MS) in multiple reaction monitoring (MRM) mode via an electrospray ionization (ESI) interface. MRM mode of precursor-product ion transitions was used for gastrodin, HBA and the internal standard (IS, bergeninum) at m/z 285.0→123.0, 123.0→105.0 and 326.9→192.2, respectively. The lower limits of quantification (LLOQ) of this method for both gastrodin and HBA were 1ng/mL, with their linear concentration ranging from 0.001 to 10μg/mL. The methods were validated for selectivity, calibration curves, accuracy and precision, extraction recoveries, matrix effects, carry-over, cross talk, dilution integrity, stability and incurred sample reanalysis (ISR). Using this validated method, pharmacokinetic behaviors of gastrodin and HBA after intragastric administration (ig) of gastrodin to dogs were studied for the first time.