Chitosan has various interesting properties, e.g., biocompatibility, biodegradability, low toxicity, antimicrobial activity, mucoadhesiveness and the ability to form hydro gels. Therefore it has been widely used in biomedicine. However, a grave obstacle in the application of chitosan is its poor solubility in water, which is limited to some diluted acid solutions. Chitosan contains amine and hydroxyl functional groups in the structure, which can be modified or grafted in order to prepare various chitosan derivatives with improved properties. Homopolypeptides or poly( amino acids) are biodegradable and biocompatible polymers used in biomedicineas alternative to the more commonly used synthetic polymers, e.g., poly(acrylic acid). Synthetic homopeptides can be prepared with a defined structure and a narrow distribution of molar masses. The most efficient synthetic route for the preparation of well-defined homopolypeptidesis the ring-opening polymerization (ROP) of a-amino acid N-carboxy anhydrides (NCA). The aim of our work was to prepare chitosan-graft-poly(L-glutamate) for application in oral delivery of high-molar-mass protein/polypeptide agents. To improve solubility of chitosan in polar organic solvents we prepared the salt of chitosan and racemic camphor-lO-sulfonic acid. For the preparation of chitosan with various lengths of poly(y-benzyl-L-glutamate) side chains we applied several [NCA]:[NH3+] feed ratios. The copolymers of chitosan and poly(y-benzyl-L-glutamate) were then deprotected under acidic conditions using HBr/AcOH in TFA to obtain chitosan-graft-poly(L- glutamate) copolymers of different molar masses.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 5048346The overview of polymers applicable in medicine were presented to BSc students.
D.10 Educational activities
COBISS.SI-ID: 5188634Chitosan is a promissing material for application in biomedical purpuses due to its interesting properties, e.g., biocompatibility, biodegradability, low toxicity, mocuadhesivness, antimicrobial activity and hydrogel forming capacity. Synthetic peptydes of defined structure and narrow molar mass distribution are prepared most effectively by the ringopening polymerization of L-á-aminoacid N-carboxyanhydrides (NCA ROP). The aim of our work was to preapare chitosan-graft-poly(L-glutamate) (chi-g-polyGlu) for oral delivery ofhigh-molar mass protein/peptide active pharmaceutical ingridients. First, we prepared a salt of chitosan and racemic camphor-10-sulfonic acid (CSA) as well as monomer NCA of ã-benzyl-Lglutamate (glu-NCA). The chitosan-graft-poly(ã-benzyl-L-glutamate) (chi-g-polyBGlu) was synthesized by NCA ROP, initiated by the protonated amine groups of the chitosan moiety. The removal of benzyl protective groups was studied under various experimental conditions: i) by HBr in the presence of an acid, ii) by alkaline hydrolysis, iii) by catalytic hydrogenation in the presence of palladium on charcoal and iiii) by trimethylsilyl iodide (TMSI).
B.06 Other
COBISS.SI-ID: 5068058