Pharmacokinetics Studies Of Total Paeony Glycosides In Rats And Interaction Of Paeoniflorin With Human Serum Albumin

Total paeony glycosides?TPG?,the main active ingredients of Paepnia lactiflora Pall and Paeonia veitchii Lynch,have pharmacological efforts including liver protection,anti-platelet aggregation,anti-atherosclerosis,antioxidation and anti-tumor.TPG consisted of paeoniflorin,albiflorin,oxypaeoniflorin.TPG was taken as research objects in this experiment,and the investigation for pharmacokinetics of TPG in normal rats and cerebral ischemia-reperfusion rats,respectively.In addition,when entering the blood,drugs will generally bind to serum albumin with varying degrees,which will affect the absorption,distribution,metabolism,excretion and efficiency effects of drugs.Paeoniflorin,as the main active components of TPG for pharmacological effects,the interaction between it and human serum albumin were studied,that the mechanism and regularity of the interaction between paeoniflorin and protein were explored at the molecular level,which provide the basic for further clinical application and development of Paeoniflorin.The research are as follows:1.Pharmacokinetics studies of Total Paeony Glycosides in rats.A simple,LC-MS/MS method was developed for the simultaneous determination of paeoniflori,albiflorin and oxypaeoniflorin in rat plasma for the first time.Applying geniposide as internal standard?IS?,detection and quantitation were performed by MS/MS using electrospray ionization?ESI?and multiple reaction monitoring?MRM?mode.The 3 analytes showed good linearity with in 0.025 ²0?g/ml?paeoniflori,albiflorin and oxypaeoniflorin?.The specificity,precisions,accuracices,extraction recoverice,matrix effects and stabilities of this experimental method were validated in accordance with the guidance for the bioanalytical methods validation.The plasma concentrations of the 3 analytes for oral and intravenous administration in normal and cerebral ischemia-reperfusion rats could be determined by the established method,then the pharmacokinetics parameters were obtained.The normal and ischemia-reperfusion model rats were immediately vio ig and iv administrated by TPG?at a dose of 235.85mg/kg and 47.17mg/kg of PF,respectively?.The concentration-time curve was fitted with PKSolver 2.0 software to analyze thepharmacokinetics parameter.The results showed,compared with normal group,the T_1/2,AUC and MRT increased in model group,it shows that the pharmacokinetics of normal group and model group are not consistent.These findings suggested that the injuries of cerebral ischemia-reperfusion could play an influence in pharmacokinetic process of TPG.2.Study on the interaction of paeoniflorinwith human serum albumin?HSA?by spectroscopicTo study the transport and metabolism of drugs in vivo,In simulative physiological condition,the interaction between human serum albumin and paeoniflorin was studied by the UV-vis spectroscopy CD spectroscopy and Molecular docking.The results clarified that the fluorescence quenching of HSA by paeoniflorin was a static quenching processand.Paeoniflorin spontaneously bound to HSA in site I?subdomain IIA?,which was primarily driven by hydrophobic forces and hydrogen bonds(?H�=-9.98 k J�mol^-1,?S�= 28.18 J�mol^-1�K^-1).The binding constant was calculated to be 1.909�10³mol/L at 288 K and it decreased with the increase of the temperature.The results of CD and three-dimensional fluorescence spectra showed that paeoniflorin induced the conformational changes of HSA.Meanwhile,the study of molecular docking also indicated that paeoniflorin could bind to the site I of HSA mainly by hydrophobic and hydrogen bond interactions.