Andreas Bernkop-Schnuerch

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Within the past 20 years, a considerable amount of work has been published on chitosan and its potential use in drug delivery systems. In contrast to all other polysaccharides having a monograph in a pharmacopeia, chitosan has a cationic character because of its primary amino groups. These primary amino groups are responsible for properties such as(More)
Due to the obvious advantages of long-acting peptide and protein drugs, strategies to prolong plasma half life time of such compounds are highly on demand. Short plasma half life times are commonly due to fast renal clearance as well as to enzymatic degradation occurring during systemic circulation. Modifications of the peptide/protein can lead to prolonged(More)
The purpose of the present study was to improve the mucoadhesive properties of alginate by the covalent attachment of cysteine. Mediated by a carbodiimide, L-cysteine was covalently linked to the polymer. The resulting thiolated alginate displayed 340.4+/-74.9 micromol thiol groups per g conjugate (means+/-S.D.; n=4). Within 2 h the viscosity of an aqueous(More)
This study examined various factors influencing the mucoadhesive properties of thiolated polymers (thiomers), which are capable of forming covalent bonds with thiol sub-structures of the mucus glycoprotein. Mediated by a carbodiimide, L-cysteine was therefore covalently bound to polycarbophil (PCP) and to carboxymethylcellulose (CMC). The resulting polymer(More)
In this study the mucoadhesive potential of nineteen different, most often referred mucoadhesive polymers was evaluated and characterized by adhesion time and total work of adhesion (TWA) of the polymer to porcine small intestinal mucosa. In addition, the influence of pH of the polymer and of method of drying on adhesion was evaluated. Aqueous polymer(More)
The aim of this study was to improve mucoadhesive properties of chitosan by the covalent attachment of thiol moieties to this cationic polymer. Mediated by a carbodiimide, thioglycolic acid (TGA) was covalently attached to chitosan. This was achieved by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid(More)
PURPOSE Purpose of the present study was the development of a mucoadhesive nanoparticulate drug delivery system for local use in intravesical therapy of interstitial cystitis, since only a small fraction of drug actually reaches the affected site by conventional treatment of bladder diseases via systemic administration. METHODS Chitosan-thioglycolic acid(More)
It was the aim of this study to develop a delivery system providing an improved efficacy of orally administered insulin utilizing a thiolated polymer. 2-Iminothiolane was covalently linked to chitosan. The resulting chitosan-TBA (chitosan-4-thiobutylamidine) conjugate exhibited 453.5+/-64.1 micromol thiol groups per gram polymer. 3.1% of these thiol groups(More)
Purpose. To improve the mucoadhesive properties of polycarbophil by the introduction of sulfhydryl groups. Methods. Mediated by a carbodiimide, cysteine was covalently bound to polycarbophil (PCP) forming amide bonds between the primary amino group of the amino acid and the carboxylic acid moieties of the polymer. The amount of covalently attached cysteine(More)
New effective antimalarial agents are urgently needed due to increasing drug resistance of Plasmodium falciparum. Phosphorothioate antisense oligodeoxynucleotides (ODNs) silencing of malarial topoisomerase II gene have shown to possess promising features as anti malarial agents. In order to improve stability and to increase intracellular penetration, ODNs(More)