Effects of borneol on the pharmacokinetics of geniposide in cortex, hippocampus, hypothalamus and striatum of conscious rat by simultaneous brain microdialysis coupled with UPLC-MS.

It has been verified that borneol could promote the accumulation of other drugs in the whole brain. In this study, a microdialysis sampling system coupled with UPLC-MS was developed to evaluate the delivery of geniposide to four brain regions (cortex, hippocampus, hypothalamus and striatum) of conscious rats in the absence/presence of borneol: rats were administrated with geniposide alone (300mg/kg, iv) or administrated with both geniposide and borneol (0.2g/kg, ig). The dialysate collected from specific brain area was analyzed by a UPLC-MS system: separated on a BEH C18 column (50mm×2.1mm id, 1.7μm) within 1.5min, and detected in positive ion electrospray mode. The calibration curve was in good linearity over the concentration range of 0.009-90μg/mL. The inter- and intra-day accuracies were within ±10%, and the precisions were within 9.13%. The established method was applied to study the brain pharmacokinetics of geniposide and the results demonstrated that borneol markedly facilitated the delivery of geniposide to hippocampus and hypothalamus, but slightly hampered its delivery in cortex.