| Peramivir has high molecular polarity due to its guanidine group,and its oral absorption is poor due to its low permeability of small intestine membrane.Oral Peramivir has been shown to have low oral availability in some experiments.Therefore,it is necessary to modify the drug to obtain higher clinical application value.In recent years,many researchers have changed the drug structure to improve its pharmacokinetic characteristics and increase its bioavailability.At present,the most common method for improving oral bioavailability is to design drugs as prodrugs.Over the years,the knowledge of drug transporters has shown that drugs are carried out through some drug transporters distributed in small intestinal epithelial cells.These transporters are used for drug delivery.The most widely used drug delivery concept for transport proteins is oligopeptide transport protein PEPT1.Based on the small intestine oligopeptide transporter PEPT1 mediated transport target,this paper screened the appropriate peramivir amino acid ester prodrug.In this study,seven peramivir amino acid ester prodrugs were synthesized by condensation reaction and catalytic hydrogenation.The structure of the product was consistent with that of the target compound.In order to carry out the next in-depth study on the prodrug of peramivir,this experiment has studied the membrane permeability of seven peramivir amino acid ester prodrugs.The analysis of the cell monolayer transport experiment shows that the membrane permeability of the seven amino acid ester prodrugs is higher than that of the mother drug peramivir,among which the membrane permeability of Peramivir-(butane-2,3-diol)-L-Val is the highest,followed by Peramivir-(2-methylpropane-1,3-diol)-L-Val.Gly-Sar(typical substrate of PEPT1)uptake experiment showed that the IC50 of Peramivir-(butane-2,3-diol)-L-Val was 1.23 ± 0.12,the IC50 of Peramivir-(butane-2,3-diol)-D-Val was 4.31 ± 0.56,the IC50 of Peramivir-(butane-2,3-diol)-L-Ile was 1.98 ± 3.8,the IC50 of Peramivir-(2-methyl-propane-1,3-diol)-L-Ile was2.13 ± 0.41,and the IC50 of Peramivir-(2-methyl-propane-1,3-diol)-L-Ala was is4.03 ± 0.67,The IC50 of Peramivir-(2-methyl-propane-1,3-diol)-D-Val is 3.02 ±0.54,and that of Peramivir-(2-methyl-propane-1,3-diol)-L-Val is 1.45 ± 0.34.The IC50 of Peramivir-(butane-23-diol)-L-Val is the smallest of all compounds,so the interaction between Peramivir-(butane-23-diol)-L-Val and PEPT1 is the strongest.To compare the uptake of peramivir amino acid ester prodrug in MDCK cells with high expression of PEPT1 and normal MDCK cells.The results showed that the uptake of seven peramivir amino acid esters in MDCK-PEPT1 cells was higher than that in normal MDCK cells.The experimental results showed that the seven amino acid ester prodrugs were the substrates of PEPT1,and they were mediated and absorbed by PEPT1 in the small intestine.The results of stability study in vitro showed that,Peramivir-(butane-2,3-diol)-L-Val,Peramivir-(butane-2,3-diol)-D-Val,Peramivir-(butane-2,3-diol)-L-Ile,Peramivir-(2-methypropane-1,3-diol)-L-Ile,Peramivir-(2-methypropane-1,3-diol)-L-Ala,the stability in hydrochloric acid phosphate buffer solution gradually decreases with the increase of PH.Peramivir-(butane-2,3-diol)-L-Val,Peramivir-(butane-2,3-diol)-L-Ile,Peramivir-(2-methypropane-1,3-diol)-L-Ile,Peramivir-(2-methypropane-1,3-diol)-L-Val),the half-life of phosphate buffer solution with p H value of 1.2 and 6.8 is higher than that of artificial gastric juice and artificial intestinal juice,respectively,so it is speculated that enzymes in the gastrointestinal tract will hydrolyze ester bonds.The stability in simulated gastric juice and small intestinal juice was found,Peramivir-(butane-2,3-diol)-L-Ile,Peramivir-(2-methypropane-1,3-diol)-L-Ala 、Peramivir-(2-methypropane-1,3-diol)-D-Val、Peramivir-(2-methypropane-1,3-diol)-L-Val),the degradation rate in rat gastric juice is slower than that in small intestine juice.It is speculated that it is mainly absorbed by small intestine in prototype and enters into the body to play its role.The results of pharmacokinetic experiments in rats showed that oral peramivir、Peramivir-(2-methypropane-1,3-diol)-L-Val 、 Peramivir-(butane-2,3-diol)-L-Ile 、Peramivir-(2-methypropane-1,3-diol)-L-Ala 、 Peramivir-(butane-2,3-diol)-D-Val 、Peramivir-(butane-2,3-diol)-L-Val 、 Peramivir-(2-methypropane-1,3-diol)-L-Ile 、Peramivir-(2-methypropane-1,3-diol)-D-Val,the bioavailability of peramivir was5.1%,44.7%,34.7%,20.2%,20.6%,49.8%,28.7% and 44.7% respectively.Therefore,oral peramivir amino acid ester prodrug can significantly improve the oral bioavailability of peramivir.To sum up,seven peramivir amino acid ester prodrugs were synthesized in this project.Through the study of intestinal membrane permeability,it was found that seven peramivir amino acid ester prodrugs was higher than that of peramivir,and the study of absorption mechanism proved that they were all substrates of PEPT1.The stability in vitro and pharmacokinetics in vivo of peramivir amino acid ester prodrug were also investigated.The results showed that the oral bioavailability of peramivir amino acid ester was higher than that of the mother drug. |
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