Plasma Pharmacokinetic Studies And Safety Evaluations Of Neopanaxadiol

Neopanaxadiol （NPD） was obtained from the acid hydrolysate of the total ginsenosidesof Panax ginseng C. A. Meyer （Araliaceae）. On the basis of spectroscopic data andsingle-crystal X-ray diffraction data, its chemical structure was elucidated to bedammar-（E）-20（22）-ene-3β,12β,25-triol. It can improve learning and memory ability ofdementia mice model. The satisfied pharmacological activity and safety make it to be apromising anti-dementia new drug candidate.To determine NPD in rat plasma after oral administration, a rapid, selective andsensitive ultra-performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method has been developed. NPD and internal standard （I.S.）,panaxadiol（PD）, were extracted from plasma （200μL） by the one-step protein precipitationwith methanol and then separated on a Waters BEH C18column using0.2%formic acidaqueous/methanol （20:80, v/v） as mobile phase at a flow rate of0.25mL/min. Massspectrometric detection utilized an API mass spectrometer equipped with an ESI（electrospray ionization） source operated in the positive ion mode. MRM （multiple reactionmonitoring） transitions were m/z461.6â†'m/z425.6for NPD and m/z461.5â†'127.0for PD.The full validation was carried out to test the specificity, accuracy, precision, matrix effects,recoveries, and stability. The linearity of the method was5¹60ng/mL, the lower limit ofquantification （LLOQ） was4ng/mL. Intra-and inter-batch precisions （as relative standarddeviation, R.S.D.） were within6.35%, and accuracy was from97.4%to104.5%. The assaywas free of interference from endogenous substances in plasma. The sample preparationprocedure can efficiently extract the analyte and I.S. with minimal matrix effects, theextraction recovery were92.3,94.5and95.4%, respectively. In the assay NPD proved to bestable under all the conditions tested. Assay validation was performed according to SFDAguidelines, because of the high sensitivity and selectivity, simple sample preparation, theresults were satisfied with the requirements of pharmacokinetic research.The NPD concentration in rat plasma was determined by the validated LC-MS/MS method. The main pharmacokinetic parameters were calculated and analyzed. After oraladministration of NPD, the pharmacokinetic parameters of6rats are as follows: Tmax:1.9±0.8h, Cmax:52.39±16.55ng/mL, t_1/2:9.61±3.98h, AUC_0-t:448.96±181.16ng/mL h,MRT（0–t）:7.47±1.67h. The concentration-time curve represent obviously double-peakphenomenon.Death was not found in rats fed with the maximum tolerance dose,6g/kg in one day,and Pathology change was not found yet. That showed the preparation was safe in acutetoxicity experiment. The physiology and biochemistry targets of every group rats andpathology examination were not altered significantly.