TY  - JOUR
AU  - Elfgen, Anne
AU  - Santiago-Schübel, Beatrix
AU  - Hupert, Michelle
AU  - Schemmert, Sarah
AU  - Schartmann, Elena
AU  - Tusche, Markus
AU  - Gering, Ian
AU  - Zafiu, Christian
AU  - Kutzsche, Janine
TI  - Oral absorption enhancement of the amyloid-β oligomer eliminating compound RD2 by conjugation with folic acid
JO  - European journal of pharmaceutical sciences
VL  - 156
SN  - 0928-0987
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2021-00351
SP  - 105581 -
PY  - 2021
AB  - Amyloid-β (Aβ) plays a central role in the development and progression of Alzheimer's disease (AD) with Aβ oligomers representing the most toxic species. The all-d-enantiomeric peptide RD2, which recently successfully completed clinical phase I, specifically eliminates Aβ oligomers in vitro as well as in vivo and improves cognitive deficits in various transgenic AD mouse models even after oral administration. To further enhance the oral absorption of RD2, folic acid has been conjugated to the d-peptide promoting an endocytosis-mediated uptake via a folate receptor located in the intestine. Two different conjugation strategies were selected to obtain prodrugs with folic acid being cleaved after intestinal absorption releasing unmodified RD2 in order to enable RD2's unaltered systemic efficacy. Both conjugates remained stable in simulated gastrointestinal fluids. But only one of them was suitable as prodrug as it was cleaved to RD2 in vitro in human blood plasma and liver microsomes and in vivo in mice after intravenous injection leading to a systemic release of RD2. Furthermore, the conjugate's permeability in vitro and after oral administration in mice was strongly enhanced compared to unconjugated RD2 demonstrating the prodrug's functionality. However, the conjugate seemed to have impaired the mice's wellbeing shortly after oral administration possibly resulting from strain-specific hypersensitivity to folic acid. Nevertheless, we assume that the prodrug is actually non-toxic, especially in lower concentrations as verified by a cell viability test. Furthermore, lower dosages can be applied with unaltered efficacy due to its enhanced oral absorption.
LB  - PUB:(DE-HGF)16
C6  - 33035662
UR  - <Go to ISI:>//WOS:000597224100001
DO  - DOI:10.1016/j.ejps.2020.105581
UR  - https://juser.fz-juelich.de/record/889730
ER  -