Liposomes coated with poly(hydroxyethyl L-glutamine) (PHEG) show prolonged circulation times and biodistribution patterns comparable to PEG-coated liposomes. While PEG is a nondegradable polymer, PHEG is expected to be hydrolyzed by proteases. In this study the enzymatic degradability of PHEG both in its free form and grafted onto liposomes was investigated, using the proteases papain, pronase E, and cathepsin B. Enzymatic action was monitored with a ninhydrin assay, which quantifies amine groups formed due to hydrolysis of amide bonds, and the degradation products were characterized by MALDI-ToF mass spectrometry. PHEG, both in its free form and when grafted onto liposomes, showed degradation into low molecular weight peptides by the enzymes. Thus, we present a polymer-coated long-circulating liposome with an enzymatically degradable coating polymer, avoiding the risk of cellular accumulation.
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http://dx.doi.org/10.1021/bc0497719 | DOI Listing |
Phys Chem Chem Phys
September 2022
Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
We perform all-atom molecular dynamics simulations of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in aqueous solutions of isobutane, propionamide, and sodium propionate. These solutes are side chain analogues to leucine, glutamine, and glutamic acid, respectively. We compute the Gibbs energy profile of the solute's adsorption to the polymer brush and decompose it into the contributions from the steric repulsion, van der Waals interaction, and Coulomb interaction to reveal the energetic origin of repulsion or attraction of the solute by the polymer brush.
View Article and Find Full Text PDFInt J Pharm
May 2008
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
The enzymatically degradable poly(amino acid)-lipid conjugate poly(hydroxyethyl l-glutamine)-N-succinyl-dioctadecylamine (PHEG-DODASuc) has been shown to effectively prolong liposome circulation times. In this paper, we investigated whether PHEG-DODASuc can stabilize liposomes composed of the fusogenic, non-bilayer-forming lipid dioleoyl phosphatidylethanolamine (DOPE). Moreover, we evaluated the release of an entrapped compound after enzyme-induced shedding of the PHEG-coating, interbilayer contact and membrane destabilizing phase changes.
View Article and Find Full Text PDFBioconjug Chem
November 2005
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands.
Liposomes coated with poly(hydroxyethyl L-glutamine) (PHEG) show prolonged circulation times and biodistribution patterns comparable to PEG-coated liposomes. While PEG is a nondegradable polymer, PHEG is expected to be hydrolyzed by proteases. In this study the enzymatic degradability of PHEG both in its free form and grafted onto liposomes was investigated, using the proteases papain, pronase E, and cathepsin B.
View Article and Find Full Text PDFBioconjug Chem
July 2004
Department of Pharmaceutics, Utrecht University, The Netherlands.
The objective of this study was to develop biodegradable polypeptide-lipid conjugates for the design of polymer-coated long-circulating liposomes (LCL). Lipid conjugates of poly(hydroxyalkyl L-asparagine/L-glutamine) were synthesized and incorporated into 0.15 microm dipalmitoyl phosphatidylcholine (DPPC)-cholesterol liposomes.
View Article and Find Full Text PDFBiosens Bioelectron
April 2002
IMTEK, Albert-Ludwigs University Freiburg, Georges Koehler Allee 103, D-79110, Freiburg, Germany.
For simultaneous measurement of glucose, lactate, glutamine, and glutamate a biosensor array is implemented in a micro flow-system thus giving a microsystem. The microsystem consists of a glass chip with the integrated biosensor array and a bottom part, which comprises a gold counter electrode, a 300 microm thick seal, and electrical interconnection lines. The flow device has a total internal volume of 2.
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