Pharmacokinetic Study Of Nanocarrier Material DSPE-PEG

Recently,nanomedicine has been extensively studied.A wide variety of nanomedicine has been developed,but relatively few have been registered for clinical trials and even fewer are clinically approved.Unsatisfactory pharmacokinetic behavior and inaccurate pharmacokinetics evaluation system contribute to their high failure rate during preclinical and clinical testing.Nowadays,most of reported studies focus on pharmacokinetics of intact nanomedicine and released drugs,but little attention is paid to pharmacokinetics of dissociated nanocarrier materials.Structural materials occupy a significant portion of nanomedicine,and greatly influence the pharmacokinetics of nanomedicine.Moreover,as xenobiotics,nanocarrier materials may cause side effects.Therefore,investigating the pharmacokinetics of nanocarrier materials is significant to the development of nanomedicine.Distearoyl phosphoethanolamine-polyethylene glycol(DSPE-PEG)is a kind of common nanocarrier material,it can achieve PEGylation and improve physicochemical and pharmacokinetic properties of nanomedicine.Many DSPE-PEG based nanomedicines have been approved for clinical use.However,up to now,no pharmacokinetic information of DSPE-PEG has been reported,and there are two main reasons.First,researchers neglected the importance of material pharmacokinetic study;second,DSPE-PEG is polydisperse,and its quantitative analysis is difficult.In this article,we developed and validated biaoanalytical methods of DSPE-PEG2000 and DSPE-PEG5000,and applied methods to pharmacokinetic studies in rats.We think our work will promote the development of DSPE-PEG based nanomedicine.1.Mass spectrum analysis of DSPE-PEG2000 and DSPE-PEG5000We analyzed mass spectrum of DSPE-PEG2000 and DSPE-PEG5000 with time of flight mass spectrometer(Q-Q-TOF).DSPE-PEG2000 and DSPE-PEG5000 are polydisperse,and their MW normally distributed around 3000 and 5000 Da.Polydispersity is caused by the structure of PEG part.In mass spectrums,DSPE-PEG2000 is mainly with 2 or 3 positive charges,and DSPE-PEG5000 with 4,5 or 6.CE(collision energy)and DP(declustering potential)can influence the charge distribution of DSPE-PEG2000 and DSPE-PEG5000,with the increase of CE and DP value,charge number decreases.DSPE-PEG2000 and DSPE-PEG5000 have similar fragmentation regularity in mass spectrometer.Both DSPE and PEG parts can produce fragment ions under the impact of CE.Fragment ion m/z 607.56 is produced by DSPE part,m/z 89.06,133.08,177.11,221.14,265.19,309.19 and 59.05,103.07,147.10,191.13,235.15 series ions are produced by PEG part.Fragment ion m/z 607.56 also can be produced via in-source collision-induced dissociation.The work in this section provides theoretical basis to the development of DSPE-PEG LC-MS quantitative methods.2.Pharmacokinetic study of DSPE-PEG2000 and DSPE-PEG5000 in rat plasmaWe developed and validated LC-MS methods for the determination of DSPE-PEG2000 and DSPE-PEG5000 in rat plasma samples,and we have investigated pharmacokinetic behavior of DSPE-PEG2000 and DSPE-PEG5000 in rats.After intravenous injection of 25 mg/kg DSPE-PEG2000 or DSPE-PEG5000 to rats,collected plasma samples were analyzed.We speculated that DSPE-PEG2000 and DSPE-PEG5000 mainly distribute in extracellular fluid,and hardly enter into cells,and distribution extent of DSPE-PEG2000 is greater than DSPE-PEG2000.Moreover,elimination rate of DSPE-PEG2000 is faster than DSPE-PEG5000.3.Tissue distribution study of DSPE-PEG2000 and DSPE-PEG5000 in ratsWe developed and validated LC-MS methods for the quantitation of DSPE-PEG2000 and DSPE-PEG5000 in rat tissue samples,and applied them to tissue distribution studies.After intravenous injection of 25 mg/kg DSPE-PEG2000 or DSPE-PEG5000 to rats,highest concentration of analytes was found in lung,and it indicates that DSPE-PEG may influence the function of lung.DSPE-PEG2000 and DSPE-PEG5000 also perform high concentration in liver,which indicates DSPE-PEG may influence the activity of liver microsomal(CYP450)enzymes,and lead to material-drug interaction.Elimination rate of DSPE-PEG2000 is slow in spleen,which may cause cumulative toxicity.Both DSPE-PEG2000 and DSPE-PEG5000 can pass through blood brain barrier and enter into brain,and DSPE-PEG5000 eliminate slowly in brain.DSPE-PEG2000 and DSPE-PEG5000 may influence the function of central nervous system.Moreover,in adipose tissue,DSPE-PEG2000 concentration is higher than DSPE-PEG5000,which may be caused by the greater polarity of DSPE-PEG2000 than DSPE-PEG5000.4.Metabolism and excretion study of DSPE-PEG2000 and DSPE-PEG5000After intravenous injection of 25 mg/kg DSPE-PEG2000 or DSPE-PEG5000 to rats,we collected urine and feces samples,and analyzed them with LC-Q-TOF.We found that both DSPE-PEG2000 and DSPE-PEG5000 can be metabolized to PEGs with different degrees of polymerization.MW range of metabolite PEGs is 500-2000 Da for DSPE-PEG2000,and 500-5000 Da for DSPE-PEG5000.Main metabolites of DSPE-PEG2000 and DSPE-PEG5000 are PEG2000 and PEG5000,and no DSPE-PEG2000 and DSPE-PEG5000 was detected in urine and feces samples.Hence,we established LC-MS methods for the quantitation of PEG2000 and PEG5000 to investigate excretion of DSPE-PEG2000 and DSPE-PEG5000.We found that renal excretion is main excretion pathway for both DSPE-PEG2000 and DSPE-PEG5000,and their total accumulative excretion rates in feces and urine are 28.02% and 49.15%.5.Study on the inhibition effects of DSPE-PEG2000 and DSPE-PEG5000 to human liver CYP450 enzymesWe established LC-MS methods for the determination of metabolites of specific probe substrate drug for seven CYP450 enzymes,and investigated inhibition effects of DSPE-PEG2000 and DSPE-PEG5000 to these enzymes.Results show that neither DSPE-PEG2000 nor DSPE-PEG5000 inhibits the activity of seven CYP450 enzymes,which means DSPE-PEG2000 and DSPE-PEG5000 can hardly interact with drugs by inhibiting CYP450 enzymes.