Preparation and Characterization of Methyl Substituted Maleic Anhydride: Modified Collagens Destined for Medical Applications

Abstract

Porous modified collagens with vinyl groups were synthesized by reaction with 2,3-dimethylmaleic anhydride or citraconic anhydride. The structure of modified collagen was assessed by analytical determination of the amino groups in collagen and spectroscopic methods (Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR)). The amount of protonated amino groups and carboxylic acid moieties of the samples have been determined by potentiometric titration. The dependence of the viscosity of diluted collagen solutions on the concentration and temperature was followed to determine their denaturation transitions. The increased average molecular weight, particle size, and second virial coefficient of modified collagen solutions with respect to the unmodified one proved that modification took place. Coupled thermal analyses (TG/DTG/DTA/FT-IR/MS) also indicated the collagen modification by increased thermal stability and new volatile compounds formed during decomposition. The adhesion tests revealed their potential application in wound dressing and tissue engineering.

pH-Responsive 2-hydroxyethyl methacrylate/citraconic anhydride–modified collagen hydrogels as ciprofloxacin carriers for wound dressings

“…Collagen is a well-known natural protein which has pK a values for both amino groups and carboxylic groups. The average pK a for the C-CA functional groups was determined by potentiometric titration method in a previous work 23 as being 4.7 for COOH groups and 10.0 for NH 2 groups. According to these findings, the pH responsiveness of the tested porous hydrogels was evaluated.…”

“…The acylation of acid-soluble collagen (C) with CA was carried out according to the method described previously. 23 Collagenase from Clostridium histolyticum (Sigma-Aldrich, USA), ninhydrin (Sigma-Aldrich, India), 2-methoxyethanol (Honeywell Fluka, Seelze, Germany), and gelatin were used for the in vitro testing of enzymatic degradation on hydrogels. CF hydrochloride monohydrate supplied from Sigma-Aldrich with purity of ⩾ 98 % and molecular weight of 385.82 g/mol was used as model drug for loading and release studies.…”

“…In our previous studies, the soluble-substituted anhydride-modified collagen macromolecules have been obtained and characterized. 23 The modified collagen was obtained by the chemical bonding between carbon atoms from the carbonyl group of citraconic anhydride (CA) and the amino group of collagen. It has a vinyl and a carboxyl group in its chemical structure.…”

Achievement of Release Mode under Combinational Stimuli by Acid and Reduction for Reduced Adverse Effect in Antitumor Efficacy

“…NH 2 ‐Dex‐SS‐NH 2 was further conjugated with CTA to introduce pH‐sensitive amide bond . Briefly, 40 mL CTA in THF (v/v, 0.5%) was added dropwise to an NH 2 ‐Dex‐SS‐NH 2 solution (2.0 mmol glucose unit) in 80 mL of phosphate buffered saline (PBS, pH 8, 0.2 mol L −1 ) under vigorous stirring.…”

Cyclic Anhydrides as Powerful Tools for Bioconjugation and Smart Delivery

“…89 Finally, citraconic and dimethylmaleic anhydrides were used to modify collagen, conferring an increased thermal stability and improved adhesion to tissues, giving the opportunity to use these adducts as wound dressings in tissue engineering. 90 10. Dimethylmaleic Anhydride (DMMA or DMA).…”