Contipro A.s.

Tomas Bobula

Vladimir Velebny

Radovan Buffa

Pavlina Prochazkova

Hana Vagnerova

Ivana Basarabova

Romana Sulakova

Petra Sedova

Lucie Wolfova

Iva Doleckova

Sona Moravcikova

Lenka Kohutova

Veronika Moravcova

Ondrej Zidek

Lenka Kovarova

The invention discloses a method of preparation of crosslinked materials based on polysaccharides using electromagnetic radiation in an aqueous solution containing a polysaccharide with a bound carbamate photoremovable protecting group (PPG with group &#x2014;NH&#x2014;CO&#x2014;O&#x2014;) and a polysaccharide containing an aldehyde group &#x2014;CHO. The crosslinking process itself is carried out by means of a condensation reaction of the photochemically released amino group (&#x2014;NH) with the aldehyde group (&#x2014;CHO) forming a bond of imine type (&#x2014;N&#x2550;CH&#x2014;). Both processes proceed simultaneously and they can be performed under physiological conditions. The advantage of the suggested solution is the temporal and spatial control of crosslinking that allows the preparation of advanced materials for tissue engineering where the crosslink density and thus the mechanical properties in the material structure can be tailored.

Method of crosslinking of polysaccharides using photoremovable protecting groups

The invention relates to the preparation of new polysaccharide derivatives comprising a double bond in the positions 4 and 5 of the pyranose cycle. The method of preparation consists in the oxidation of OH group in the position 6 to an aldehyde, followed by the elimination to form a double &#x2014;C&#x2550;C&#x2014; bond in the positions 4 and 5, and the final reduction of the aldehyde group in the position 6 into the original alcohol. The derivatives of polysaccharides prepared according to the invention show an enhanced antioxidant activity and some of them also a selective negative influence on carcinoma cell viability. (formula) where R represents &#x2014;NH&#x2014;CO&#x2014;CHor &#x2014;OH. 

Unsaturated derivatives of polysaccharides, method of preparation thereof and use thereof

The invention relates to the preparation and the use of &#x3b1;,&#x3b2;-unsaturated aldehydes in the structure of sulfated polysaccharides. It concerns the derivatives with a conjugated double bond in the 4th and 5th positions of the galactopyranose part situated in the 6th position with respect to the aldehyde, according to the general structural formula (I) or its hydrated form according to the general structural formula (II). The preparation of these derivatives derives from sulfated polysaccharides containing a galactopyranose ring sulfated in the 4th position that is bound in the polymer chain via &#x3b1;(1&#x2192;3) or &#x3b2;(1&#x2192;3) O-glycosidic bond. In the described solution, the sulfated polysaccharides undergo a regio- and chemoselective oxidation to form C6-saturated aldehyde, which, via a direct elimination of the sulfate group, provides the &#x3b1;,&#x3b2;-unsaturated derivative according to the general formula (I) or (II). The described solution is technically advantageous, because it leads directly to &#x3b1;,&#x3b2;-unsaturated aldehydes, without any elimination agents, higher temperature, or isolation of intermediates during the synthesis. The conjugation in the structure of &#x3b1;,&#x3b2;-unsaturated aldehyde allows, under physiological conditions, to bind a wide variety of biocompatible amines in the structure of the sulfated polysaccharides. The proposed method allows to prepare materials suitable for pH-responsive drug delivery systems, or for the preparation of scaffolds in tissue engineering or regenerative medicine. Formulae for the abstract (I), (II) above, where R is OH, O&#x2014;SO&#x2014;OH, O&#x2014;SO&#x2014;ONa, or NH&#x2014;Ac. 

Derivatives of sulfated polysaccharides, method of preparation, modification and use thereof

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Svit, Slovakia

Tomas Bobula