Synthesis, structural characterization and properties of water-soluble N-(γ-propanoyl-amino acid)-chitosans

Abstract

Water-soluble peptide-chitosans were obtained by reaction of low-molecular-weight chitosan, having a low degree of acetylation, with peptide substituents under mild conditions. These peptide substituents were prepared by standard peptide chemistry from 3bromopropanoic acid and tert-butyl esters of the a-amino acids glycine and phenylalanine. The structure of the new peptide-chitosan polymers was confirmed by proton nuclear magnetic resonance and infrared spectroscopy. The thermotropic and morphological properties of both the new peptide-chitosans and two other analogues, derived from valine and aspartic acid [synthesis reported in

Facile Regioselective Synthesis of a Novel Chitosan–Pexiganan Conjugate with Potential Interest for the Treatment of Infected Skin Lesions

“…4) glycoside bridge at 1153 cm À1 and 899 cm À1 . [12,13] In comparison, the FT-IR spectrum of the peptide conjugate (Fig. 1b), while still displaying the characteristic bands due to the polysacharide chains (O-H bending at À1 , C-O stretching at 1079 cm À1 , C-O-C stretching vibration in the glucopyranose ring at 1036 cm À1 and the specific bands of the b(1 !…”

“…[6] This was followed by the latest (as of 13 March 2008) press release on new phase III clinical trials promoted by this company that confirm the efficacy of pexiganan to be statistically equivalent to that of oral antibiotic therapy. [7] Taking advantage of our prior experience in the synthesis and study of antimicrobial peptides, [8][9][10] as well as in the development of novel chitosan-based biopolymers for biomedical applications, [11][12][13] we decided to break through to the preparation of a novel chitosan-pexiganan conjugate with potential application in the topical treatment of infected diabetic foot ulcers. We hope such a conjugate will combine the excellent antimicrobial properties of pexiganan with the well-known biocompatibility and skin-injury-healing ability of chitosan.…”

Elimination of inter- and intramolecular crosslinks of phosphorylated chitosan by sodium salt formation

“…Its poor water solubility has been a major drawback in its use in pharmaceutical and biomedical applications. Several attempts have been made to improve the water solubility of chitosan through several chemical modifications such as chitosan-graft-poly (ethylene glycol) methyl ether, 1 chitosan-gallic acid, 2 N-(g-propanoylamino acid)-chitosans, 3 N-acylated or N-alkylated chitosan, 4 O-succinyl-chitosan 5 and chitosan-L-glutamic acid, 6 among others. However, this research focuses on the chemical modification of chitosan with phosphoric groups.…”

Interaction of chitosan and chitin with Ni, Cu and Zn ions: A computational study

“…Note that in the case of N-acetylglucosamine, there are two different possibilities for the metal coordination at c4 and c5 positions due to rotation of the acetyl group. Thus, the metals can bind O (4) For each of the five different interaction sites studied on the two chitosan monomers, selected geometric parameters are reported in table 2, while the interaction energies and enthalpies at T = 298.15 K are reported in table 3. Additionally, figure 3 shows a For atomic labelling see figure 1.…”

“…Chitosan is non-toxic and biodegradable, and possesses optimal sorption properties, easily establishing stable complexes with metal ions [1]. Chemical modifications of the parent polymer are usually performed for enhancing its selectivity, chelating properties, solubility and antioxidant properties [2][3][4]. Thus, several biological and environmental applications are known where chitosan-based materials are used for, e.g., controlled drug release in vivo, due to their remarkable biocompatibility, mucoadhesive and tissue regenerating properties, or water decontamination by removal of heavy metals from aqueous media [5].…”