RESUMEN
OBJECTIVE: To establish a measuring method for microdialysis probe recovery of ginsenoside Rg1 and investigate the effects of flow rate, concentration and using times of probe on the recovery in vivo and in vitro. METHODS: Dialysis method and retrodialysis method were used for the study. The concentration of ginsenoside Rg1 in brain and blood dialysate was determined by LC-MS /MS and the probe recovery was calculated. RESULTS: The recoveries of brain and blood microdialysis probes showed good stability within 10 h, with average values of 17.0% and 34.4% respectively for ginsenoside Rg1 at 1.5 μL•min-1. Concentrations (50, 200, 500, 1 000 ng•mL-1) had no obvious effect on recovery. At the same concentration, the recovery of brain and blood probes for ginsenoside Rg1 decreased with the increase of flow rate (0.5, 1.0, 1.5, 2.0, 3.0 μL• min-1) in vitro and in vivo. The dialysis recoveries of brain and blood probes in vitro were (40.6 ± 4.3)%, (23.5 ± 2.3)%, (17.7 ± 0.8 )%, (12.2 ± 1.1)%, (8.8 ± 0.6)% and (70.6 ± 3.6)%, (46.0 ± 2.1)%, (32.9 ± 1.6)%, (25.6 ± 0.7)%, (18.2 ± 1.3)%, respectively. The recoveries of dialysis and retrodialysis in vitro were approximately equal, and the recovery detected by retrodialysis in vivo was similar with the in vitro results. Probe used for no more than 3 times still kept high transmittance by flushing with 2% heparin sodium and ultrapure water successively. CONCLUSION: Retrodialysis method can be used to study brain and blood probe recovery in vivo, and microdialysis can be used for simutaneous pharmacokinetic studies of ginsenoside Rg1 in intercelluar fluid and blood.