口服地西他滨拟肽类前药的设计与评价
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摘要
地西他滨属核苷类抗肿瘤药物,2006年在美国上市,主要用于骨髓增生异常综合症的治疗,是迄今为止应用最广泛及很有前景的DNA去甲基化抑制剂。地西他滨在体内经脱氧胞苷激酶转化成活性的三磷酸地西他滨,三磷酸地西他滨插入DNA从而抑制DNA的去甲基化,抑制癌细胞的生长。但地西他滨由于有糖基的存在,分子极性很大,导致小肠膜通透性差；而且地西他滨在体内容易被肠道黏膜和肝脏的胞嘧啶脱氨酶作用脱氨,生成无活性的尿苷地西他滨,因此地西他滨口服生物利用度低(仅为9%),在临床上主要以静脉注射的方式给药。目前尚未见对地西他滨进行结构改造以提高口服生物利用度的报道,这样研究适合口服给药的地西他滨前药是非常有意义的。本课题的设计思路是研发出可以被小肠寡肽转运蛋白(oligopeptide transporter1, PepT1)特异识别的地西他滨前药,提高地西他滨的膜渗透性,进而提高其口服生物利用度。
本研究首先通过酰化反应和催化氢化合成了5个地西他滨的L-缬氨酸、D-缬氨酸、L-异亮氨酸、L-苯丙氨酸和L-色氨酸酯前药,并优化了合成路线和分离纯化方法,使得反应条件较为简单可行且提高了目标产物的收率。
利用Caco-2细胞模型研究了5个地西他滨5'位氨基酸酯类前药和母药地西他滨的膜通透性,其中L-缬氨酸酯前药(5'-O-L-valyl-dac)和L-苯丙氨酸酯前药(5'-O-L-phenylanlanyl-dac)的膜渗透率较高,分别为9.94×10-7和1.13×10-6cm/s,是地西他滨的3.28和3.75倍。基于结构的差异和膜渗透性的考虑,选择了脂肪族的5'-O-L-valyl-dac和芳香族的5'-O-L-phenylanlanyl-dac作为代表性的先导化合物,对其吸收机制、稳定性和体内药物动力学进行深入研究。
Gly-Sar(PepTl的典型底物)的摄取抑制实验表明,Gly-Sar的摄取可以被5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac所抑制,且呈现浓度依赖性,半数抑制浓度(IC50)分别是2.20±0.28mM and3.46±0.16mM;母药DAC对Gly-Sar的摄取几乎没有抑制作用。利用瘦素(leptin)来诱导Caco-2细胞高表达PepTl,实验结果表明,和正常Caco-2细胞相比,5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的摄取在leptin诱导的Caco-2细胞上有显著提高；而母药地西他滨的摄取没有显著提高。综上,体外细胞实验表明5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac均为PepT1的底物,而母药地西他滨不是PePT1的底物。
体外稳定性研究结果表明,化合物5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac在系列pH值磷酸盐缓冲液中的稳定性随着pH的升高而逐渐下降。5'-O-L-valyl-dac在小肠匀浆、肝匀浆和血浆中的半衰期分别为61,5和86min,5'-O-L-phenylanlanyl-dac在小肠匀浆、肝匀浆半衰期分别为7和2min,血中半衰期极短,没有检测到。在大鼠胃液、小肠液中,两个化合物都在1.5h以上,较为稳定。这预示着前药在胃肠道中应该能保持较好的稳定性,经肠道PePT1介导吸收后在体内应该能很快的生物活化为地西他滨,发挥药理活性。此外,相对于5'-O-L-valyl-dac,5'-O-L-phenylanlanyl-dac进入体内后能够更加快速地激活。
大鼠体内药动学研究表明,相同剂量下(15mg/kg,以地西他滨计),口服5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的生物利用度分别由口服地西他滨的26.9%提高到46.7%和50.9%。另外体内吸收抑制性实验表明,同时给服Gly-Sar(150mg/kg),会导致两个化合物吸收降低,但仍高于口服母药地西他滨,一方面说明了Gly-Sar可以抑制PepTl对5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的转运,另一方面也说明了PepTl的转运能力比较强,属于高转运容量的载体蛋白,基于它的相互作用强度并不显著。
Decitabine (DAC) is nucleoside anti-neoplastic drugs and it was approved by the FDA for the treatment of myelodysplastic syndrome (MDS) in May2006. To date, it has been the most extensively and advanced investigated DNA methyltransferase (DNMT) inhibitor although there are abundant DNMT inhibitors undergoing preclinical and clinical evaluation. In vivo, DAC is phosphorylated by deoxycytidine kinase to form an active metabolite,5-azadeoxycytidine triphosphate, which is then incorporated into DNA strands and prevents DNA methylation. However, the great molecular polarity of DAC can cause poor intestinal membrane permeability. Due to rapid deamination to the biologically inactive5-aza-2'-deoxyuridine in intestinal and hepatic cells, DAC exhibits a very short plasma half-life and a very low oral bioavailability (about9%), which necessitates the continuous infusion to maintain therapeutical plasma level clinically. But as far as we know there was no report of peptidomimetic prodrugs of DAC. The purpose of paper was to develop the prodrug that could be specifically identified by intestinal PepTl (oligopeptide transporter1) and increase membrane permeability. So that the prodrug could enhance the oral bioavailability of DAC, raise patient compliance and reduce individual differences.
Five amino acid prodrugs of DAC (L-valine, D-valine, L-isoleucine, L-phenylalanine and L-tryptophan prodrug) were synthesized through acylation reaction and catalytic hydrogenation. And we optimized the synthetic route and purification method for the simple and practicable reaction condition and increasing the yield of targeted products.
The transport characteristics of the five prodrugs were studied in Caco-2cells to screen the target compound with high permeability. Among the compounds,5'-L-valyl-dac (9.94X10-7cm/s) and5'-O-L-phenylanlanyl-dac(1.13×10-6cm/s) possess higher permeability, which were3.28and3.75times as high as DAC, respectively. Meanwhile, based on high permeability and different amino acid promoieties,5'-O-L-valyl-dac (aliphatic) and5'-O-L-phenylanlanyl-dac (aromatic) were selected as the lead compounds for further study, such as uptake mechanism, stability and in vivo pharmacokinetics.
Gly-Sar (a typical substrate of PepT1) uptake inhibition experiments indicated that Gly-Sar uptake could be inhibited by5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac as a concentration-dependent. The half inhibition concentration (50%inhibitory concentration, IC50) were2.20±0.28mM and3.46±0.16mM, respectively. DAC did not exhibit any inhibition at all the tested concentrations. Leptin was used to induce high expression of PepTl in Caco-2cells. And the uptake of Gly-Sar by the leptin-treated Caco-2cells was compared with the control Caco-2cells to evaluate whether this treatment was successful. The uptake of5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac in leptin-induced Caco-2cell was more than in the control Caco-2cells significantly, while the uptake of DAC are not significantly different between the leptin-treated and control Caco-2cells. In vitro uptake experiments showed that the two compounds were substrates of PepTl, while DAC lacked any apparent affinity for the transporter.
The stability experiments were performed in phosphate buffers of different pH values, rat tissue homogenates, plasma, gastric and intestinal fluids at37℃. The chemical stability of5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac was notably influenced by the pH value of phosphate buffer. The chemical stability of two prodrugs basically decreased with the increasing pH of phosphate buffer. The t1/2values of5'-O-L-valyl-dac in the intestinal homogenates, hepatic homogenates and plasma were61,5and86min, respectively. The ti/2values of5'-O-L-phenylanlanyl-dac in the intestinal homogenates and hepatic homogenates were7and2min, the half-life of the compound in plasma was extremely short and5'-O-L-phenylanlanyl-dac could not be detected. In the rat gastric fluids and intestinal fluids, the half-lives of the two compounds both were greater than1.5h. This implied that the two compounds could maintain enough chemical stability in gastrointestinal tract and was rapidly converted to active parent drug by ester enzymes following PepTl-mediated transport across the intestinal membrane.5'-O-L-phenylanlanyl-dac had a higher in vivo bioconversion rate compared to5'-O-L-valyl-dac.
The oral absolute bioavailability of DAC following oral administration of5'-O-L-valyl-dac,5'-O-L-phenylanlanyl-dac and DAC to rats at a dose of15mg/kg (calculated as DAC dose) was46.7%,50.9%and26.9%, respectively. When oral coadministration with PepTl typical substrate, Gly-Sar (150mg/kg), the absolute bioavailability of DAC following oral administration of prodrug to rats decreased from46.7%to32.2%for5'-O-L-valyl-dac and from50.9%to32.5%for 5'-O-L-phenylanlanyl-dac, respectively.
本研究首先通过酰化反应和催化氢化合成了5个地西他滨的L-缬氨酸、D-缬氨酸、L-异亮氨酸、L-苯丙氨酸和L-色氨酸酯前药,并优化了合成路线和分离纯化方法,使得反应条件较为简单可行且提高了目标产物的收率。
利用Caco-2细胞模型研究了5个地西他滨5'位氨基酸酯类前药和母药地西他滨的膜通透性,其中L-缬氨酸酯前药(5'-O-L-valyl-dac)和L-苯丙氨酸酯前药(5'-O-L-phenylanlanyl-dac)的膜渗透率较高,分别为9.94×10-7和1.13×10-6cm/s,是地西他滨的3.28和3.75倍。基于结构的差异和膜渗透性的考虑,选择了脂肪族的5'-O-L-valyl-dac和芳香族的5'-O-L-phenylanlanyl-dac作为代表性的先导化合物,对其吸收机制、稳定性和体内药物动力学进行深入研究。
Gly-Sar(PepTl的典型底物)的摄取抑制实验表明,Gly-Sar的摄取可以被5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac所抑制,且呈现浓度依赖性,半数抑制浓度(IC50)分别是2.20±0.28mM and3.46±0.16mM;母药DAC对Gly-Sar的摄取几乎没有抑制作用。利用瘦素(leptin)来诱导Caco-2细胞高表达PepTl,实验结果表明,和正常Caco-2细胞相比,5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的摄取在leptin诱导的Caco-2细胞上有显著提高；而母药地西他滨的摄取没有显著提高。综上,体外细胞实验表明5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac均为PepT1的底物,而母药地西他滨不是PePT1的底物。
体外稳定性研究结果表明,化合物5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac在系列pH值磷酸盐缓冲液中的稳定性随着pH的升高而逐渐下降。5'-O-L-valyl-dac在小肠匀浆、肝匀浆和血浆中的半衰期分别为61,5和86min,5'-O-L-phenylanlanyl-dac在小肠匀浆、肝匀浆半衰期分别为7和2min,血中半衰期极短,没有检测到。在大鼠胃液、小肠液中,两个化合物都在1.5h以上,较为稳定。这预示着前药在胃肠道中应该能保持较好的稳定性,经肠道PePT1介导吸收后在体内应该能很快的生物活化为地西他滨,发挥药理活性。此外,相对于5'-O-L-valyl-dac,5'-O-L-phenylanlanyl-dac进入体内后能够更加快速地激活。
大鼠体内药动学研究表明,相同剂量下(15mg/kg,以地西他滨计),口服5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的生物利用度分别由口服地西他滨的26.9%提高到46.7%和50.9%。另外体内吸收抑制性实验表明,同时给服Gly-Sar(150mg/kg),会导致两个化合物吸收降低,但仍高于口服母药地西他滨,一方面说明了Gly-Sar可以抑制PepTl对5'-O-L-valyl-dac和5'-O-L-phenylanlanyl-dac的转运,另一方面也说明了PepTl的转运能力比较强,属于高转运容量的载体蛋白,基于它的相互作用强度并不显著。
Decitabine (DAC) is nucleoside anti-neoplastic drugs and it was approved by the FDA for the treatment of myelodysplastic syndrome (MDS) in May2006. To date, it has been the most extensively and advanced investigated DNA methyltransferase (DNMT) inhibitor although there are abundant DNMT inhibitors undergoing preclinical and clinical evaluation. In vivo, DAC is phosphorylated by deoxycytidine kinase to form an active metabolite,5-azadeoxycytidine triphosphate, which is then incorporated into DNA strands and prevents DNA methylation. However, the great molecular polarity of DAC can cause poor intestinal membrane permeability. Due to rapid deamination to the biologically inactive5-aza-2'-deoxyuridine in intestinal and hepatic cells, DAC exhibits a very short plasma half-life and a very low oral bioavailability (about9%), which necessitates the continuous infusion to maintain therapeutical plasma level clinically. But as far as we know there was no report of peptidomimetic prodrugs of DAC. The purpose of paper was to develop the prodrug that could be specifically identified by intestinal PepTl (oligopeptide transporter1) and increase membrane permeability. So that the prodrug could enhance the oral bioavailability of DAC, raise patient compliance and reduce individual differences.
Five amino acid prodrugs of DAC (L-valine, D-valine, L-isoleucine, L-phenylalanine and L-tryptophan prodrug) were synthesized through acylation reaction and catalytic hydrogenation. And we optimized the synthetic route and purification method for the simple and practicable reaction condition and increasing the yield of targeted products.
The transport characteristics of the five prodrugs were studied in Caco-2cells to screen the target compound with high permeability. Among the compounds,5'-L-valyl-dac (9.94X10-7cm/s) and5'-O-L-phenylanlanyl-dac(1.13×10-6cm/s) possess higher permeability, which were3.28and3.75times as high as DAC, respectively. Meanwhile, based on high permeability and different amino acid promoieties,5'-O-L-valyl-dac (aliphatic) and5'-O-L-phenylanlanyl-dac (aromatic) were selected as the lead compounds for further study, such as uptake mechanism, stability and in vivo pharmacokinetics.
Gly-Sar (a typical substrate of PepT1) uptake inhibition experiments indicated that Gly-Sar uptake could be inhibited by5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac as a concentration-dependent. The half inhibition concentration (50%inhibitory concentration, IC50) were2.20±0.28mM and3.46±0.16mM, respectively. DAC did not exhibit any inhibition at all the tested concentrations. Leptin was used to induce high expression of PepTl in Caco-2cells. And the uptake of Gly-Sar by the leptin-treated Caco-2cells was compared with the control Caco-2cells to evaluate whether this treatment was successful. The uptake of5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac in leptin-induced Caco-2cell was more than in the control Caco-2cells significantly, while the uptake of DAC are not significantly different between the leptin-treated and control Caco-2cells. In vitro uptake experiments showed that the two compounds were substrates of PepTl, while DAC lacked any apparent affinity for the transporter.
The stability experiments were performed in phosphate buffers of different pH values, rat tissue homogenates, plasma, gastric and intestinal fluids at37℃. The chemical stability of5'-O-L-valyl-dac and5'-O-L-phenylanlanyl-dac was notably influenced by the pH value of phosphate buffer. The chemical stability of two prodrugs basically decreased with the increasing pH of phosphate buffer. The t1/2values of5'-O-L-valyl-dac in the intestinal homogenates, hepatic homogenates and plasma were61,5and86min, respectively. The ti/2values of5'-O-L-phenylanlanyl-dac in the intestinal homogenates and hepatic homogenates were7and2min, the half-life of the compound in plasma was extremely short and5'-O-L-phenylanlanyl-dac could not be detected. In the rat gastric fluids and intestinal fluids, the half-lives of the two compounds both were greater than1.5h. This implied that the two compounds could maintain enough chemical stability in gastrointestinal tract and was rapidly converted to active parent drug by ester enzymes following PepTl-mediated transport across the intestinal membrane.5'-O-L-phenylanlanyl-dac had a higher in vivo bioconversion rate compared to5'-O-L-valyl-dac.
The oral absolute bioavailability of DAC following oral administration of5'-O-L-valyl-dac,5'-O-L-phenylanlanyl-dac and DAC to rats at a dose of15mg/kg (calculated as DAC dose) was46.7%,50.9%and26.9%, respectively. When oral coadministration with PepTl typical substrate, Gly-Sar (150mg/kg), the absolute bioavailability of DAC following oral administration of prodrug to rats decreased from46.7%to32.2%for5'-O-L-valyl-dac and from50.9%to32.5%for 5'-O-L-phenylanlanyl-dac, respectively.
引文
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[12]Yan Z. T., Sun J., Chang, Y. N., et al. Bifunctional Peptidomimetic Prodrugs of Didanosine for Improved Intestinal Permeability and Enhanced Acidic Stability: Synthesis, Transepithelial Transport, Chemical Stability and Pharmacokinetics. Mol. Pharmaceutics 2011,8,319-329.
[13]Han H., de Vrueh R.L., Rhie J.K., et al.5'-Amino acid esters of antiviral nucleosides, acyclovir, and AZT are absorbed by the intestinal PepTl peptide transporter. Pharm Res,1998,15(8):1154-1159.
[1]Han H.K., Oh D.M., Amidon G.L. Cellular uptake mechanism of amino acid ester prodrugs in Caco-2/hPEPT1 cells overexpressing a human peptide transporter. Pharm Res, 1998,15(9):1382-1386.
[2]Han H.K., Rhie J.K., Oh D.M., et al. CHO/hPEPT1 cells overexpressing the human peptide transporter (hPEPT1) as an alternative in vitro model for peptidomimetic drugs. J Pharm Sci,1999,88(3):347-350.
[3]Chu C., Okamoto C.T., Hamm-Alvarez S.F., et al. Stable transfection of MDCK cells with epitope-tagged human PepTl. Pharm Res,2004,21(11):1970-1973.
[4]Chen H., Pan Y.X., Wong E.A., et al. Characterization and regulation of a cloned ovine gastrointestinal peptide transporter (oPepT1) expressed in a mammalian cell line. J Nutr, 2002,132(1):38-42.
[5]Nduat V., Yan Y. T., Dalmasso G., et al. Leptin transcriptionally enhances peptide transporter(hPepTl) expression and activity via Camp-response elementbingind pritein Cdx2 transportion factors. J Biol Chem,2007,282 (2):1359-1373.
[6]Hindlet P., Bado A., Farinotti R., et al. Long-term effect of leptin on H+-coupled peptide cotransporterl activity and expression in vivo:evidence in leptin-deficient mice. J Pharmacol Exp Ther,2007,323(1):192-201.
[7]Nabulsi N.B., Smith D.E., Kilbourn M.R. [11C]Glycylsarcosine:synthesis and in vivo evaluation as a PET tracer of PepT2 transporter function in kidney of PepT2 null and wild-type mice. Bioorg Med Chem,2005,13(8):2993-3001.
[8]S(?)ndergaard HB, Brodin B, Nielsen CU. hPEPT1 is responsible for uptake and transport of Gly-Sar in the human bronchial airway epithelial cell-line Calu-3. Pflugers Arch,2008, 456(3):611-622.
[9]Majumdar S, Kansara V, Mitra AK. Pharmacokinetics of dipeptide monoester prodrugs of ganciclovir. J Ocul Pharmacol Ther,2006,22(4):231-241.
[10]Sun Y, Sun J, Liu J, et al.Rapid and sensitive hydrophilic interaction chromatography/tandem mass spectrometry method for the determination of glycyl-sarcosine in cell homogenates. J Chromatogr B,2009,877(7):649-652.
[11]Li, F.J.; Maag. H.; Alfredson. T. Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting. J. Pharm. Sci.2008,97(3),1109-1133.
[12]Schlichtherle-Cerny, H.; Affolter, M., Cerny, C. Hydrophilic interaction liquid chromatography coupled to electrospray mass spectrometry of small polar compounds in food analysis. Anal. Chem. 2003,75,2349-2354.
[13]Dejaegher B, Mangelings D, Vander Heyden Y. Method development for HILIC assays. J Sep Sci,2008,31(9):1438-1448.
[14]Terada T, Inui K. Peptide transporters:structure, function, regulation and application for drug delivery [J]. Curr. Drug Metab,2004,5(1):85-94.
[15]侯新朴.主编.物理化学(第四版).人民卫生出版社.
[16]Granero G.E., Amino GL. Stability of valacyclovir:implication for its oral bioavailability. Int. J Pharm,2006,317(1):14-18.
[17]Kim, I.; Chu, X.Y.; Kim, S.Y.; Provoda, C.J.; Lee K.D.; Amino, G. L. Identification of a human valacyclovirase:biphenyl hydrolasease-like protein as valacyclovir hydrolase. J. Biol. Chem.2003,278(28),25348-25356.
[18]Talluri R.S., Samanta S.K., Gaudana R., et al. Synthesis, metabolism and cellular permeability of enzymatically stable dipeptide prodrugs of acyclovir. Int J Pharm,2008 361(1-2):118-124.
[19]Cheon E.P., Hong J.H., Han H.K. Enhanced cellular uptake of ara-C via a peptidomimetic prodrug, L-valyl-ara-C in Caco-2 cells. J Pharm Pharmacol,2006, 58(7):927-932.
[1]Zhang Y.X., Sun J., Gao Y.K., et al. An HPLC-MS/MS method for simultaneous determination of decitabine and its valyl prodrug valdecitabine in rat plasma. J. Chromatogr. B.2013,917-918,78-83.
[2]Li, F.J.; Maag. H.; Alfredson. T. Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting. J. Pharm. Sci.2008,97(3),1109-1133.
[3]Chae KA, Cho HJ, Sung JM, et al. Bioavailability of the amino acid-attached prodrug as a new anti-HIV agent in rats. J Vet Sci 2007,8(3):263-267.
[4]Ogihara T, Kano T, Wagatsuma T, et al. Oseltamivir (tamiflu) is a substrate of peptide transporter 1. Drug Metab Dispos,2009,37(8):1676-1681.
[5]Liu Z.F., Marcucci G., Byrd J. C., et al. Characterization of decomposition products and preclinical and low dose clinical pharmacokinetics of decitabine (5-aza-2'-deoxycytidine) by a new liquid chromatography/tandem mass spectrometry quantification method. Rapid Commun. Mass Spectrom.2006,20:1117-1126.
[6]Lin K.T., Momparler R.L., Rivard E.G. Sample preparation and estimation of plasma concentration of 3-deazauridine by high-performance liquid chromatography. Rivard, Ther. Drug Monit.1983,5(4):491-496.
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[8]Patel K., Guichard S.M., Jodrell D.I., Simultaneous determination of decitabine and vorinostat (Suberoylanalide hydroxamic acid, SAHA) by liquid chromatography tandem mass spectrometry for clinical studies J. Chromatogr. B.2008,863(1):19-25.
[9]Cashen A.F., Shah A.K., Todt L., et al. Pharmacokinetics of decitabine administered as a 3-h infusion to patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Cancer Chemother. Pharmacol.2008,61(5):759-766.
[10]Xu H.Y., M Q.X., Fu Y., et al.Development and validation of a liquid chromatography-tandem mass spectrometry method for quantification of decitabine in rat plasma. J. Chromatogr. B,2012,899:81-85.
[11]Sun J., Dahan A., Amidon G.L. Enhancing the intestinal absorption of molecules containing the polar guanidino functionality:a double-targeted prodrug approach. J Med Chem,2010; 53(2):624-632.
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[11]Song X., Lorenzi P.L., Landowski C.P., et al. Amino acid ester prodrugs of the anticancer agent gemcitabine:synthesis, bioconversion, metabolic bioevasion, and hPEPT1-mediated transport. Mol Pharm,2005,2(2):157-167.
[12]Yan Z. T., Sun J., Chang, Y. N., et al. Bifunctional Peptidomimetic Prodrugs of Didanosine for Improved Intestinal Permeability and Enhanced Acidic Stability: Synthesis, Transepithelial Transport, Chemical Stability and Pharmacokinetics. Mol. Pharmaceutics 2011,8,319-329.
[13]Han H., de Vrueh R.L., Rhie J.K., et al.5'-Amino acid esters of antiviral nucleosides, acyclovir, and AZT are absorbed by the intestinal PepTl peptide transporter. Pharm Res,1998,15(8):1154-1159.
[1]Han H.K., Oh D.M., Amidon G.L. Cellular uptake mechanism of amino acid ester prodrugs in Caco-2/hPEPT1 cells overexpressing a human peptide transporter. Pharm Res, 1998,15(9):1382-1386.
[2]Han H.K., Rhie J.K., Oh D.M., et al. CHO/hPEPT1 cells overexpressing the human peptide transporter (hPEPT1) as an alternative in vitro model for peptidomimetic drugs. J Pharm Sci,1999,88(3):347-350.
[3]Chu C., Okamoto C.T., Hamm-Alvarez S.F., et al. Stable transfection of MDCK cells with epitope-tagged human PepTl. Pharm Res,2004,21(11):1970-1973.
[4]Chen H., Pan Y.X., Wong E.A., et al. Characterization and regulation of a cloned ovine gastrointestinal peptide transporter (oPepT1) expressed in a mammalian cell line. J Nutr, 2002,132(1):38-42.
[5]Nduat V., Yan Y. T., Dalmasso G., et al. Leptin transcriptionally enhances peptide transporter(hPepTl) expression and activity via Camp-response elementbingind pritein Cdx2 transportion factors. J Biol Chem,2007,282 (2):1359-1373.
[6]Hindlet P., Bado A., Farinotti R., et al. Long-term effect of leptin on H+-coupled peptide cotransporterl activity and expression in vivo:evidence in leptin-deficient mice. J Pharmacol Exp Ther,2007,323(1):192-201.
[7]Nabulsi N.B., Smith D.E., Kilbourn M.R. [11C]Glycylsarcosine:synthesis and in vivo evaluation as a PET tracer of PepT2 transporter function in kidney of PepT2 null and wild-type mice. Bioorg Med Chem,2005,13(8):2993-3001.
[8]S(?)ndergaard HB, Brodin B, Nielsen CU. hPEPT1 is responsible for uptake and transport of Gly-Sar in the human bronchial airway epithelial cell-line Calu-3. Pflugers Arch,2008, 456(3):611-622.
[9]Majumdar S, Kansara V, Mitra AK. Pharmacokinetics of dipeptide monoester prodrugs of ganciclovir. J Ocul Pharmacol Ther,2006,22(4):231-241.
[10]Sun Y, Sun J, Liu J, et al.Rapid and sensitive hydrophilic interaction chromatography/tandem mass spectrometry method for the determination of glycyl-sarcosine in cell homogenates. J Chromatogr B,2009,877(7):649-652.
[11]Li, F.J.; Maag. H.; Alfredson. T. Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting. J. Pharm. Sci.2008,97(3),1109-1133.
[12]Schlichtherle-Cerny, H.; Affolter, M., Cerny, C. Hydrophilic interaction liquid chromatography coupled to electrospray mass spectrometry of small polar compounds in food analysis. Anal. Chem. 2003,75,2349-2354.
[13]Dejaegher B, Mangelings D, Vander Heyden Y. Method development for HILIC assays. J Sep Sci,2008,31(9):1438-1448.
[14]Terada T, Inui K. Peptide transporters:structure, function, regulation and application for drug delivery [J]. Curr. Drug Metab,2004,5(1):85-94.
[15]侯新朴.主编.物理化学(第四版).人民卫生出版社.
[16]Granero G.E., Amino GL. Stability of valacyclovir:implication for its oral bioavailability. Int. J Pharm,2006,317(1):14-18.
[17]Kim, I.; Chu, X.Y.; Kim, S.Y.; Provoda, C.J.; Lee K.D.; Amino, G. L. Identification of a human valacyclovirase:biphenyl hydrolasease-like protein as valacyclovir hydrolase. J. Biol. Chem.2003,278(28),25348-25356.
[18]Talluri R.S., Samanta S.K., Gaudana R., et al. Synthesis, metabolism and cellular permeability of enzymatically stable dipeptide prodrugs of acyclovir. Int J Pharm,2008 361(1-2):118-124.
[19]Cheon E.P., Hong J.H., Han H.K. Enhanced cellular uptake of ara-C via a peptidomimetic prodrug, L-valyl-ara-C in Caco-2 cells. J Pharm Pharmacol,2006, 58(7):927-932.
[1]Zhang Y.X., Sun J., Gao Y.K., et al. An HPLC-MS/MS method for simultaneous determination of decitabine and its valyl prodrug valdecitabine in rat plasma. J. Chromatogr. B.2013,917-918,78-83.
[2]Li, F.J.; Maag. H.; Alfredson. T. Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting. J. Pharm. Sci.2008,97(3),1109-1133.
[3]Chae KA, Cho HJ, Sung JM, et al. Bioavailability of the amino acid-attached prodrug as a new anti-HIV agent in rats. J Vet Sci 2007,8(3):263-267.
[4]Ogihara T, Kano T, Wagatsuma T, et al. Oseltamivir (tamiflu) is a substrate of peptide transporter 1. Drug Metab Dispos,2009,37(8):1676-1681.
[5]Liu Z.F., Marcucci G., Byrd J. C., et al. Characterization of decomposition products and preclinical and low dose clinical pharmacokinetics of decitabine (5-aza-2'-deoxycytidine) by a new liquid chromatography/tandem mass spectrometry quantification method. Rapid Commun. Mass Spectrom.2006,20:1117-1126.
[6]Lin K.T., Momparler R.L., Rivard E.G. Sample preparation and estimation of plasma concentration of 3-deazauridine by high-performance liquid chromatography. Rivard, Ther. Drug Monit.1983,5(4):491-496.
[7]Lin K.T., Momparler R.L., Rivard G.E., Sample preparation for the determination of 5-aza-2'-deoxycytidine in plasma by high-performance liquid chromatography. J. Chromatogr.1985,345(1):162-167.
[8]Patel K., Guichard S.M., Jodrell D.I., Simultaneous determination of decitabine and vorinostat (Suberoylanalide hydroxamic acid, SAHA) by liquid chromatography tandem mass spectrometry for clinical studies J. Chromatogr. B.2008,863(1):19-25.
[9]Cashen A.F., Shah A.K., Todt L., et al. Pharmacokinetics of decitabine administered as a 3-h infusion to patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Cancer Chemother. Pharmacol.2008,61(5):759-766.
[10]Xu H.Y., M Q.X., Fu Y., et al.Development and validation of a liquid chromatography-tandem mass spectrometry method for quantification of decitabine in rat plasma. J. Chromatogr. B,2012,899:81-85.
[11]Sun J., Dahan A., Amidon G.L. Enhancing the intestinal absorption of molecules containing the polar guanidino functionality:a double-targeted prodrug approach. J Med Chem,2010; 53(2):624-632.