Objective: To establish a measuring method for in vitro and in vivo recovery of microdialysis probe of notoginsenoside R1 and to investigate the effect of flow rate

drug concentration and usage count of probe on recovery

then in vivo stability of probe recovery was investigated. Method: Dialysis method and retrodialysis method were used for this study.The concentration of notoginsenoside R1 in brain and blood dialysate was determined by LC-MS/MS and the probe recovery was calculated. Result: The recovery of brain and blood microdialysis probe showed a good stability within 10 h

the average recoveries of brain and blood probe when flow velocity at 1.5 μL·min-1 for notoginsenoside R1 were 14.0%and 33.2%

respectively.At the same concentration

the in vitro and in vivo recoveries of brain and blood probe of notoginsenoside R1 decreased with the increase of flow rate (0.5

1.0

1.5

2.0

3.0 μL·min-1).The dialysis recoveries of brain and blood probe in vitro were (36.0±1.7)%

(23.5±1.6)%

(14.2±0.5)%

(8.0±0.7)%

(5.4±0.5)% and (61.6±2.6)%

(48.0±4.1)%

(33.0±2.8)%

(24.1±1.2)%

(18.9±1.1)%

respectively.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.Concentrations (50

200

500

1 000 μg·L-1) had no obvious effect on recovery at constant flow rate.Probe which used no more than 3 times could still keep high transmittance by syringe with 2% heparin sodium and ultrapure water successively. Conclusion: Retrodialysis method can be used to study probe recovery of notoginsenoside R1

and microdialysis can be used for pharmacokinetic study of notoginsenoside R1.