Supercritical Impregnation of Mesoglycan and Lactoferrin on Polyurethane Electrospun Fibers for Wound Healing Applications

Production of mono and bilayer devices for wound dressing by coupling of electrospinning and supercritical impregnation techniques

In this paper, electrospinning and supercritical impregnation were coupled to produce polyurethane fibrous membranes loaded with mesoglycan and lactoferrin. The proposed methodology allowed the production of three skin wound healing bilayer systems: a first system containing mesoglycan loaded through electrospinning and lactoferrin loaded by supercritical impregnation, a second system where the use of the two techniques was reversed, and a third sample where the drugs were both encapsulated through a one-step process. SEM analysis demonstrated the formation of microfibers with a homogeneous drug distribution. The highest loadings were 0.062 g/g for mesoglycan and 0.013 g/g for lactoferrin. Then, hydrophilicity and liquid retention analyses were carried out to evaluate the possibility of using the manufacturers as active patches. The kinetic profiles, obtained through in vitro tests conducted using a Franz diffusion cell, proved that the diffusion of the active drugs followed a double-step release before attaining the equilibrium after about 30 h. When the electrospun membranes were placed in contact with HUVEC, HaCaT, and BJ cell lines, as human endothelial cells, keratinocytes, and fibroblasts, respectively, no cytotoxic events were assessed. Finally, the capacity of the most promising system to promote the healing process was performed by carrying out scratch tests on HaCat cells.

Supercritical Antisolvent Precipitation of Corticosteroids/β-Cyclodextrin Inclusion Complexes

In this study, corticosteroid-β-cyclodextrin (β-CD) inclusion complexes were prepared by using supercritical antisolvent (SAS) precipitation to enhance the dissolution rate of dexamethasone (DEX) and prednisolone (PRED), which are poorly water soluble drugs. The processing of the active principles in the absence of a carrier led to their almost complete extraction (the small amount of obtained material precipitates in the form of crystals). The coprecipitation of the ingredients in the presence of β-CD was investigated at different concentrations, pressures, and molar ratios. For both the corticosteroids, the optimized operating conditions were 40 °C, 120 bar, an equimolar ratio, and a concentration in DMSO of 20 mg/mL; these conditions led to the attainment of microparticles with mean diameters equal to 0.197 ± 0.180 μm and 0.131 ± 0.070 μm in the case of DEX and PRED, respectively. Job's method confirmed the formation of inclusion complexes with a 1/1 mol/mol ratio. Compared to the pure ingredients, the obtained powders have an improved release rate, which is about three times faster in both cases. The release curves obtained under the best operating conditions were fitted using different models. The best fitting was obtained using the Weibull model, whose parameters are compatible with a combined release mechanism involving Fickian diffusion and controlled release.

An Advanced Review: Polyurethane-Related Dressings for Skin Wound Repair

The inability of wounds to heal effectively through normal repair has become a burden that seriously affects socio-economic development and human health. The therapy of acute and chronic skin wounds still poses great clinical difficulty due to the lack of suitable functional wound dressings. It has been found that dressings made of polyurethane exhibit excellent and diverse biological properties, but lack the functionality of clinical needs, and most dressings are unable to dynamically adapt to microenvironmental changes during the healing process at different stages of chronic wounds. Therefore, the development of multifunctional polyurethane composite materials has become a hot topic of research. This review describes the changes in physicochemical and biological properties caused by the incorporation of different polymers and fillers into polyurethane dressings and describes their applications in wound repair and regeneration. We listed several polymers, mainly including natural-based polymers (e.g., collagen, chitosan, and hyaluronic acid), synthetic-based polymers (e.g., polyethylene glycol, polyvinyl alcohol, and polyacrylamide), and some other active ingredients (e.g., LL37 peptide, platelet lysate, and exosomes). In addition to an introduction to the design and application of polyurethane-related dressings, we discuss the conversion and use of advanced functional dressings for applications, as well as future directions for development, providing reference for the development and new applications of novel polyurethane dressings.