An LC/MS quantitative and microdialysis method for cyclovirobuxine D pharmacokinetics in rat plasma and brain: The pharmacokinetic comparison of three different drug delivery routes

• We developed liquid chromatography-tandem mass spectrometry method for CVB-D.
• An in vivo microdialysis method was used in rat plasma and brain for the first time.
• We investigated the pharmacokinetics of CVB-D taken via three delivery routes.
• Intranasal administration was able to effectively deliver the CVB-D to the brain.

To explore the brain-targeting of cyclovirobuxine D(CVB-D) after administered intranasally, the pharmacokinetics of CVB-D via three different drug delivery routes: intragastric (i.g.), intranasal (i.n.), and intravenous (i.v.) in rat brain and blood was compared. Firstly, an in vivo microdialysis method for sampling CVB-D in both plasma and brain of the rat was established. Secondly, a liquid chromatography-tandem mass spectrometry method has been developed and validated for determination of CVB-D in microdialysis samples. For plasma and brain microdialysis samples, liquid–liquid extraction was used and donepezil was chosen as internal standard. Both were followed by HPLC separation and positive electrospray ionization tandem mass spectrometry detection (ESI–MS/MS). Chromatographic separation was achieved on a agilent C18 column with a mobile phase of methanol–water (50:50, v/v) (pH 3.2) containing 0.1% formic acid and 5 mM ammonium acetate. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (MRM) of the transitions at m/z 403.4 → 372.3 for CVB-D and m/z 380.2 → 243.1 for donepezil (IS). Good linearities were obtained in the range of 10–4000 ng/mL in rat microdialysates for CVB-D. The lowest limit of quantitation was 5 ng/mL, with an extraction recovery >75%, and no significant matrix effects. Intra- and inter-day precisions were all <15% with accuracies of 97.26–116.20%. All of which proved that the established method was successfully applied to the pharmacokinetic study of CVB-D. Simultaneously, brain uptake and pharmacokinetic studies were performed by determination of CVB-D concentration in blood and brain respectively for CVB-D i.g., i.n. and i.v.. Results showed that the intranasal CVB-D could improve brain targeting and had advantages for direct nose to brain transport of CVB-D when compared with injection and oral delivery routes, which indicates that intranasal administration of CVB-D could be a promising approach for the treatment of cerebrovascular disease.