The Studies On Pharmacokinetics And Tissue Distribution Of Pmea Prodrugs By Hplc With Fluorescence Detection

Adefovir dipivoxil (ADV) is new generation nucleoside anti-virus drug.ADV rapidly metabolizes to the active substance adeofvir (PMEA) in vivo,which is a prodrug of PMEA.Studies in vitro and vivo have shown that PMEA may not only fight effectively against wild hepatitis B virus (HBV)but that it may obviously restrain HBV resistant to lamivudine.It was widely used to anti-virus in the therapy of chronic hepatitis B (CHB). In the studies on animals and human, the oral prodrug of PMEA,ADV shows potential dose-limiting kidney toxicity.Toxic effects and severity of the drug have a positive correlation with dose and time,which has limited the clinical application to a certain extent.It is necessary to explore new drugs to substitute ADV.M1, M2 are the newly synthetic prodrugs of adefovir,whose structures are similar to ADV.To study the early pharmacokinetics and tissue distribution of the two,we compared the relative bioavailability of M1, M2 with ADV as the beagle dogs and wister rats for the objects of research,using ADV for the reference standard drug. Because M1, M2 rapidly metabolize to the active substance PMEA in vivo, we can reflect the alteration of concentrations of M1 and M2 in the animals blood and tissue distribution through determining the concentration of PMEA.This thesis established method separately to determinate the concentration of PMEA in plasma of beagle dogs and tissues of wister rats by HPLC with fluorescence detection and validated the method systematically.Through animal experiments,the thesis screened and compared the analogs M1 and M2 with ADV of PMEA distribution in plasma of beagle dogs and tissues of wister rats and provided a theoretical foundation for further exploitation of new dugs anti-HBV.Part I:establishment of HPLC with fluorescence detection for the determination of PMEA in the plasma of beagle dogs.We studied the pharmacokinetics of ADV, M1 and M2 in beagle dogs and compared the relative bioavailability of the three drugs,verified the method of HPLC with fluorescence detection systematically as PMEA for the determination drug,tenofovir(PMPA) for the internal standard.PMEA was treated with chloroacetaldehyde to yield the corresponding highly fluorescent 1,N6-ethenoadenine derivative.Pharmacokinetic study showed that: after drench administration,the average drug concentration in plasma: ADV> M1>M2.The comparison on the results of relative bioavailability: AUCM1/AUCADV=56.79%, AUCM2/AUCADV=42.90%.Part II:establishment of HPLC with fluorescence detection for the determination of PMEA in rat tissues.We researched the distribution of ADV,M1 and M2 in liver,kidney of rats and verified the method of HPLC with fluorescence detection systematically as PMEA for the determination drug,PMPA for the internal standard. PMEA was treated with chloroacetaldehyde to yield the corresponding highly fluorescent 1,N6-ethenoadenine derivative.Tissue distribution study shows that: in the liver: M2>M1>ADV,in the kidney: ADV>M1>M2, M2 improved the distribution of PMEA in the liver,it has better targeting to the liver than M1 and ADV and lower nephrotoxicity.