TY - JOUR

T1 - Pyrimidine and nucleoside gamma-esters of L-Glu-Sar

T2 - synthesis, stability and interaction with hPEPT1

AU - Eriksson, André H

AU - Elm, Peter L

AU - Begtrup, Mikael

AU - Brodin, Birger

AU - Nielsen, Robert

AU - Steffansen, Bente

N1 - Keywords: Bioreversible derivatives; Dipeptide; Aqueous stability; hPEPT1; Caco-2; Intracellular pH

PY - 2005

Y1 - 2005

N2 - The aim of the present study was to improve the synthetic pathway of bioreversible dipeptide derivatives as well as evaluate the potential of using l-Glu-Sar as a pro-moiety for delivering three newly synthesised nucleoside and pyrimidine l-Glu-Sar derivatives. l-Glu(trans-2-thymine-1-yl-tetrahydrofuran-3-yl ester)-Sar (I), l-Glu(thymine-1-yl-methyl ester)-Sar (II) and l-Glu(acyclothymidine)-Sar (III) were synthesised and in vitro stability was studied in various aqueous and biological media. Affinity to and translocation via hPEPT1 was investigated in mature Caco-2 cell monolayers, grown on permeable supports. Affinity was estimated in a competition assay, using [14C] labelled Gly-Sar (glycylsarcosine). Translocation was measured as pHi-changes induced by the substrates using the fluorescent probe BCECF and an epifluorescence microscope setup. All dipeptide derivatives released the model drugs quantitatively by specific base-catalysed hydrolysis at pH>6.0. II was labile in aqueous buffer solution, whereas I and III showed appropriate stability for oral administration. In 10% porcine intestinal homogenate, the half-lives of the dipeptide derivatives indicated limited enzyme catalyzed degradation. All compounds showed good affinity to hPEPT1, but the Compounds I and III showed not to be translocated by hPEPT1. The translocation of the l-Glu-Sar derivative of acyclovir, l-Glu(acyclovir)-Sar was also investigated and showed not to take place. Consequently, l-Glu-Sar seems to be a poor pro-moiety for hPEPT1-mediated transport.

AB - The aim of the present study was to improve the synthetic pathway of bioreversible dipeptide derivatives as well as evaluate the potential of using l-Glu-Sar as a pro-moiety for delivering three newly synthesised nucleoside and pyrimidine l-Glu-Sar derivatives. l-Glu(trans-2-thymine-1-yl-tetrahydrofuran-3-yl ester)-Sar (I), l-Glu(thymine-1-yl-methyl ester)-Sar (II) and l-Glu(acyclothymidine)-Sar (III) were synthesised and in vitro stability was studied in various aqueous and biological media. Affinity to and translocation via hPEPT1 was investigated in mature Caco-2 cell monolayers, grown on permeable supports. Affinity was estimated in a competition assay, using [14C] labelled Gly-Sar (glycylsarcosine). Translocation was measured as pHi-changes induced by the substrates using the fluorescent probe BCECF and an epifluorescence microscope setup. All dipeptide derivatives released the model drugs quantitatively by specific base-catalysed hydrolysis at pH>6.0. II was labile in aqueous buffer solution, whereas I and III showed appropriate stability for oral administration. In 10% porcine intestinal homogenate, the half-lives of the dipeptide derivatives indicated limited enzyme catalyzed degradation. All compounds showed good affinity to hPEPT1, but the Compounds I and III showed not to be translocated by hPEPT1. The translocation of the l-Glu-Sar derivative of acyclovir, l-Glu(acyclovir)-Sar was also investigated and showed not to take place. Consequently, l-Glu-Sar seems to be a poor pro-moiety for hPEPT1-mediated transport.

KW - Biological Transport

KW - Caco-2 Cells

KW - Dipeptides

KW - Drug Stability

KW - Humans

KW - Hydrogen-Ion Concentration

KW - Nucleosides

KW - Prodrugs

KW - Pyrimidines

KW - Symporters

U2 - 10.1016/j.ejps.2005.02.007

DO - 10.1016/j.ejps.2005.02.007

M3 - Journal article

C2 - 15854810

VL - 25

SP - 145

EP - 154

JO - Norvegica Pharmaceutica Acta

JF - Norvegica Pharmaceutica Acta

SN - 0928-0987

IS - 1

ER -