TY  - JOUR
A1  - Wöhl-Bruhn, Stefanie
A1  - Badar, Muhammad
A1  - Bertz, Andreas
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Menzel, Henning
A1  - Müller, Peter P.
A1  - Bunjes, Heike
T1  - Comparison of in vitro and in vivo protein release from hydrogel systems
JF  - Journal of controlled release
N2  - Hydrogel systems based on hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA) or hydroxyethyl starch methacrylate (HES-MA) were used to assess the protein release behavior. Here, we analyzed the in vitro release of FITC-anti-human antibodies incorporated in either HES-P(EG)(6)MA or HES-MA hydrogel delivery systems in PBS or human serum. In addition, hydrogel disks and microparticles prepared from the two polymers were subcutaneously implanted in BALB/c mice. The in vivo release of FITC-IgG was non-invasively monitored by an in vivo imaging system (IVIS 200) over a time period of up to 3 months. The imaging system allowed to asses individual animals over time, therefore only a small number of animals was required to obtain high quality data. The reduction in fluorescence intensity at the site of administration was compared to in vitro release profiles. These investigations demonstrated a sustained release from HES-MA hydrogel disks compared to rapidly degrading HES-P(EG)(6)MA disks and microparticles. The sustained release from HES-MA disks could be further optimized by using increased polymer concentrations. Human serum as in vitro release medium reflected better the in vivo release from HES-P(EG)(6)MA systems than PBS, suggesting that the presence of organic substances like proteins or lipids may play a significant role for the release kinetics.
KW  - In vivo imaging system (IVIS)
KW  - Hydrogel disks
KW  - Hydrogel microparticles
KW  - Release
KW  - In vivo-in vitro correlation
KW  - Hydroxyethyl starch (HES)
Y1  - 2012
U6  - https://doi.org/10.1016/j.jconrel.2012.05.049
SN  - 0168-3659
VL  - 162
IS  - 1
SP  - 127
EP  - 133
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wessig, Pablo
A1  - Gerngross, Maik
A1  - Freyse, Daniel
A1  - Bruhn, P.
A1  - Przezdziak, Marc
A1  - Schilde, Uwe
A1  - Kelling, Alexandra
T1  - Molecular Rods Based on Oligo-spiro-thioketals
JF  - The journal of organic chemistry
N2  - We report on an extension of the previously established concept of oligospiroketal (OSK) rods by replacing a part or all ketal moieties by thioketals leading to oligospirothioketal (OSTK) rods. In this way, some crucial problems arising from the reversible formation of ketals are circumvented. Furthermore, the stability of the rods toward hydrolysis is considerably improved. To successfully implement this concept, we first developed a number of new oligothiol building blocks and improved the synthetic accessibility of known oligothiols, respectively. Another advantage of thioacetals is that terephthalaldehyde (TAA) sleeves, which are too flexible in the case of acetals can be used in OSTK rods. The viability of the OSTK approach was demonstrated by the successful preparation of some OSTK rods with a length of some nanometers.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.joc.5b02670
SN  - 0022-3263
VL  - 81
SP  - 1125
EP  - 1136
PB  - American Chemical Society
CY  - Washington
ER  -