Composite Fish Collagen-Hyaluronate Based Lyophilized Scaffolds Modified with Sodium Alginate for Potential Treatment of Chronic Wounds

Hyaluronic acid/tannic acid films for wound healing application

In this study, thin films based on hyaluronic acid (HA) with tannic acid (TA) were investigated in three different weight ratios (80HA/20TA, 50HA/50TA, 20HA/80TA) for their application as materials for wound healing. Surface free energy, as well as their roughness, mechanical properties, water vapor permeability rate, and antioxidant activity were determined. Moreover, their compatibility with blood and osteoblast cells was investigated. The irritation effect caused by hyaluronic acid/tannic acid films was also considered with the use of are constructed human epidermis model. The irritation effect for hyaluronic acid/tannic acid films by the in vitro method was also studied. The low surface free energy, surface roughness, and antioxidant activity presented by the obtained films were examined. All the tested compositions of hyaluronic acid/tannic acid films were hemocompatible, but only films based on 50HA/50TA were fully cytocompatible. Regarding the potential implantation, all the films except 80HA/20TA showed appropriate mechanical properties. The specimens did not exert the irritation effect during the studies involving reconstructed human epidermis.

Water-soluble chitosan eases development of mucoadhesive buccal films and wafers for children

Oromucosal films and wafers are user-friendly solid dosage forms offering easy and convenient administration, as well as rapid or controlled drug delivery. The aim of this study was to develop prednisolone containing child-friendly chitosan-based mucoadhesive films and wafers with a prolonged residence time on the buccal mucosa. Four different chitosan types (different molecular weights, degree of deacetylation (DDA), pattern of deacetylation) were studied for films prepared by solvent-cast-evaporation and wafers by freeze-drying. Mucoadhesive properties correlated with swelling abilities and were dependent on the chitosan type, the solvent, and the preparation method. Mucoadhesive forces were higher for formulations containing chitosan with higher DDA and for wafers compared to films. The drug release was relatively fast, especially for films (approx. 90 % in 15 minutes) and steadier for wafers (90 % in 45-120 minutes). Permeability was evaluated using artificial membranes and HT29-MTX cell-monolayers. The developed formulations exhibited good biocompatibility. Organoleptic properties can be improved by choosing a homogenously deacetylated chitosan type that provides a more neutral pH. Using hydroxypropyl-beta-cyclodextrin-complexation for taste masking of bitter drugs also reduced wafers' drug release rate. Mucoadhesive wafers are promising alternatives to films with a slower drug release rate and stronger mucoadhesion.

Collagen type II-hyaluronan interactions - the effect of proline hydroxylation: a molecular dynamics study

Hyaluronan-collagen composites have been employed in numerous biomedical applications. Understanding the interactions between hyaluronan and collagen is particularly important in the context of joint cartilage function and the treatment of joint diseases. Many factors affect the affinity of collagen for hyaluronan. One of the important factors is the ratio of 3- or 4-hydroxy proline to proline residues. This article presents the results from molecular dynamics calculations of HA-collagen type II interactions with hyaluronan. The applied protocol employed docking and geometry optimization of complexes built using collagen structures with different numbers of hydroxyl groups attached to proline moieties. It was established that the hydroxyproline/proline ratio affects both structural and energetic features of the collagen-hyaluronan complex. Proline hydroxylation was found to significantly influence the number of all identified types of molecular forces, hydrophobic interactions, water bridges and hydrogen bonds, which can be formed between collagen and hyaluronan. Importantly, an increase in the hydroxyproline/proline ratio in the collagen chain increases the binding affinity for hyaluronan. This is illustrated by the linear correlation between the binding free energy and the hydroxylation degree. A comparison of the results obtained for 3 and 4 hydroxylation of proline indicates that the hydroxyl group attachment position plays a minor role in complex stabilization. However, a slightly stronger affinity was observed for 4 hydroxylation. In order to evaluate the effect of the aqueous environment on the collagen-hyaluronan complex stability, the enthalpic and entropic contributions to the free energy of solvation were analyzed.