Hyaluronic acid (HA) is a biocompatible, mucosal-interacting polysaccharide that offers unique advantages for oral drug delivery. Chemical modification with hydrophobic groups transforms HA into an amphiphilic polymer capable of self-assembly and encapsulation of poorly soluble compounds. In this work, we developed an oral delivery system based on oleyl-hyaluronate (O-HA) for coenzyme Q10 (CoQ10), a lipophilic antioxidant with limited solubility and low bioavailability. The coenzyme Q10-loaded oleyl-hyaluronate nanoparticles (O-HAQ10) were prepared using a multistep solvent evaporation method, achieving a high CoQ10 loading of up to 13.8 g/L and an encapsulation efficiency typically exceeding 90

The self-assembly of polymer-based drug carriers plays a critical role in their performance in drug delivery and targeting. In this study, we investigated the effect of various salts on the aggregation behavior of oleoyl-modified hyaluronic acid (OL-HA) and its functional properties. Structural organization was assessed by dynamic light scattering, atomic force microscopy, scanning electron cryomicroscopy, surface tension, rheology and steady-state and time-resolved fluorescence (probes pyrene, Nile red and perylene), revealing that zinc acetate promotes self-assembly compared to water and phosphate-buffered saline, forming smaller (12 vs. 24 nm) and more compact hydrophobic domains with higher microviscosity (388 vs. 35 mPa∙s in Zn(Ac)2 compared to PBS). These structural improvements translated into a substantial increase in drug loading capacity, with curcumin showing a 20% enhancement (50.5 vs. 42.2 μg/ml) and imidazole-based antimicrobial agents up to a 45-fold improvement (miconazole content reached 386.0 μg/ml in Zn(Ac)2 vs. 8.3 μg/ml in PBS). Beyond loading, zinc acetate remarkably boosted the biological performance of OL-HA carriers: curcumin penetration into skin increased by 69%, antifungal-loaded systems demonstrated efficient skin permeation (reaching 43% for bifonazole), formed distinct inhibition zones against Candida albicans (zone diameter up to 5.4 ± 0.6 mm) and prevented Aspergillus brasiliensis colonization (up to 0% coverage), and zinc acetate-containing formulation achieved the greatest wound closure of 84.5 ± 10.3% in keratinocyte scratch assays. This study establishes a structure-property-function relationship for OL-HA and highlights zinc acetate as a simple yet powerful excipient for tuning the self-assembly and efficacy of HA-based nanocarriers.

This study presents the successful encapsulation of coenzyme Q10 (CoQ10) within sodium oleoyl hyaluronate (O-HA; Mw ∼12,000 Da) nanoparticles, creating a concentrated, liquid colloidal dispersion. The nanoprecipitation process achieved high encapsulation efficiency (up to 96%) and a loading capacity of 2.4-3.0 mg·mL-1. The physicochemical properties of these solid polymeric nanoparticles, including particle size (240-295 nm) and negative zeta potential (-50 to -53 mV), were optimized to ensure colloidal stability. Long-term stability assessments demonstrated unusual CoQ10 retention and colloidal integrity within this liquid system. The nanoparticles exhibited 90% chemical retention after six months at 40 °C, and maintained their initial particle size (∼273 nm) and zeta potential (∼-53 mV), with 92% chemical retention after one year and 83% after two years at 25 °C. Biological studies revealed that O-HAQ10 nanoparticles enhanced bioactivity, providing protection against reactive oxygen species and exerting anti-inflammatory effects (upregulation of HMOX1, downregulation of IL-6) at cellular exposure concentrations of 4-40 µg·mL-1. Increased expression of collagen types IV and VII suggested a role in reducing signs of aging. Due to CoQ10's extreme lipophilicity and high molecular weight, its effective partitioning into viable skin layers is severely restricted. Therefore, to facilitate dermal delivery, the aqueous nanoparticle dispersion was incorporated into a ∼40:60 water-in-oil (W/O) emulsion using sorbitan olivate as a non-ionic emulsifier. In vitro penetration studies demonstrated that W/O emulsion significantly enhanced skin absorption by 3.8-fold compared to unencapsulated CoQ10 and commercial liposomal formulations. These findings establish O-HAQ10 nanoparticles as a promising, stable delivery system for dermatological applications.

Polysaccharides like hyaluronan (HA) and chondroitin sulfate (CS) are native of the brain's extracellular matrix crucial for myelination and brain maturation. Despite extensive research on HA and CS as drug delivery systems (DDS), their high water solubility limits their application as drug carriers. This study introduces an injectable DDS using aldehyde-modified hyaluronic acid (HAOX) hydrogel containing polyelectrolyte complexes (PEC) formed with calcium, gelatin, and either CS or aldehyde-modified CS (CSOX) to deliver minocycline for Multiple Sclerosis therapy. PECs with CSOX enable covalent crosslinking to HAOX, creating immobilized PECs (HAOX_PECOX), while those with CS remain unbound (HAOX_PECS). The in situ forming DDS can be administered via a 20 G needle, with rapid gelation preventing premature leakage. The system integrates into an implanted device for minocycline release through either Fickian or anomalous diffusion, depending on PEC immobilization. HAOX_PECOX reduced burst release by 88 %, with a duration of 127 h for 50 % release. The DDS exhibited an elastic modulus of 3800 Pa and a low swelling ratio (0-1 %), enabling precise control of minocycline release kinetics. Released minocycline reduced IL-6 secretion in the Whole Blood Monocytes Activation Test, suggesting that DDS formation may not alter the biological activity of the loaded drug.

All-trans-retinoic acid (atRA) is a potent ligand that regulates gene expression and is used to treat several skin disorders. Hyaluronic acid (HA) was previously conjugated with atRA (HA-atRA) to obtain a novel amphiphilic compound. HA-atRA forms micelles that incorporate hydrophobic molecules and facilitate their transport through the skin. The aim of this study was to determine the influence of HA-atRA on gene expression in skin cells and to compare it with that of unbound atRA. Gene expression was investigated using microarrays and a luciferase system with a canonical atRA promoter. HA-atRA upregulated gene expression similarly to atRA. However, HA-atRA activated the expression of cholesterol metabolism genes, unlike atRA. Further investigation using HPLC and filipin III staining suggested that the treated cells induced cholesterol synthesis to replenish the cholesterol removed from the cells by HA-atRA. HA modified with oleate (HA-C18:1) removed cholesterol from the cells similarly to HA-atRA, suggesting that the cholesterol removal stemmed from the amphiphilic nature of the two derivatives. HA-atRA induces retinoid signaling. Thus, HA-atRA could be used to treat skin diseases, such as acne and psoriasis, where the combined action of atRA signaling and anti-inflammatory cholesterol removal may be potentially beneficial.

Nanofibrous materials are used in drug delivery as carriers of active ingredients. These can be incorporated into the materials with various electrospinning methods that differ mainly in the way spinning solutions are prepared. Each method affects primarily the encapsulation efficiency and distribution of active ingredients in the materials. This study focuses on the incorporation of octenidine dihydrochloride (OCT) and triclosan (TRI) into nanofibrous materials electrospun from native hyaluronic acid emulsions, dispersions, and blends. OCT had no substantial effect on fiber morphology, which is affected by the solvent system. All OCT encapsulation efficiencies were comparable (approximately 90%). TRI encapsulation efficiencies varied greatly depending on the method used. Merely 3% of TRI was encapsulated when it was spun from a dispersion. Encapsulation efficiency was higher, and TRI was incorporated in clusters when an emulsion was used. The best result was achieved with a blend, in which case 96% of TRI was encapsulated.

Lauroyl derivatives of hyaluronan are safe and biodegradable materials that seem promising for application in medicine. However, their potential in the field of drug delivery was not yet explored. We thus prepared lauroyl hyaluronan films loaded with various drugs and studied the effects of lauroyl hyaluronan properties, drug hydrophobicity and medium composition on the drug release. Since biomolecules will always be present in real clinical applications, media supplemented by albumin were also included. The amphiphilic character of lauroyl hyaluronan enabled convenient loading of the films by both hydrophilic and hydrophobic drugs. Dominant factors influencing drug release were drug hydrophobicity and the presence of albumin. Hydrophilic diclofenac was released rapidly in all cases, while triclosan with medium hydrophobicity exhibited slower release sensitive to other parameters, reaching equilibrium values in the used experimental setup. The release of hydrophobic octenidine into pure buffer was almost negligible, but the addition of albumin did promote its release. The strong effect of albumin highlights the importance of considering biomolecules in the design of release experiments.

Hyaluronan (HA) is widely used for eye drops as lubricant to counteract dry eye disease. High and low molecular weight HA are currently used in ophthalmology. However, a large portion of the current literature on friction and lubrication addresses articular (joint) cartilage. Therefore, eye drops compositions based on HA and its derivatized forms are extensively characterized providing data on the tribological and mucoadhesive properties. The physiochemical properties are investigated in buffers used commonly in eye drops formulations. The tribological investigation reveals that amphiphilic HA-C12 decreases the friction coefficient. At the same time, the combination of trehalose/HA or HAC12 enhances up to eighty-fold the mucoadhesiveness. Thus, it is predicted a prolonged residence time on the surface of the eye. The incorporation of trehalose enhances the protection of human keratinocytes (HaCaT) cells, as demonstrated in an in-vitro cell-desiccation model. The presence of trehalose increases the friction coefficient. Medium molecular weight HA shows significantly lower friction coefficient than high molecular weight HA. This research represents a first, wide array of features of diverse HA forms for eye drops contributing to increase the knowledge of these preparations. The results here presented also provide valuable information for the design of highly performing HA-formulations addressing specific needs before preclinic.

Due to their large active surface, high loading efficiency, and tunable dissolution profiles, nanofibrous mats are often cited as promising drug carriers or antimicrobial membranes. Hyaluronic acid has outstanding biocompatibility, but it is hydrophilic. Nanofibrous structures made from hyaluronan dissolve immediately, making them unsuitable for controlled drug release and longer applications. We aimed to prepare a hyaluronan-based antimicrobial nanofibrous material, which would retain its integrity in aqueous environments. Self-supporting nanofibrous mats containing octenidine dihydrochloride or triclosan were produced by electrospinning from hydrophobized hyaluronan modified with a symmetric lauric acid anhydride. The nanofibrous mats required no cross-linking to be stable in PBS for 7 days. The encapsulation efficiency of antiseptics was nearly 100%. Minimal release of octenidine was observed, while up to 30% of triclosan was gradually released in 72 h. The nanofibrous materials exhibited antimicrobial activity, the fibroblast viability was directly dependent on the antiseptic content and its release.

Different methods and materials can be used for peptide synthesis. One of the most common approaches is synthesis on a solid phase. In this paper, we describe fibres based on hyaluronic acid (HA) and their properties under solid-phase peptide synthesis (SPPS) conditions. The fibres were prepared by wet spinning technology and were used to study their stability and mechanical properties under the reaction conditions for direct peptide synthesis or conjugation with a pre-synthesized peptide. Fibres in the form of a non-woven textile were then used as a proof of concept for the adhesion of cells on short cell-adhesion peptides. The methods, solvents and reaction conditions used showed no significant influence on the necessary stability of the HA fibres when the Fmoc/tBu strategy was applied. Furthermore, the stability of the HA fibres in aqueous solution was strongly improved. The stabilization and presence of cell-adhesive peptides supported the adhesion of cardiomyocyte cells, which confirmed the functionality of the modified textile. Therefore, HA carriers bearing peptides could be advantageously employed in various biomedical applications as repair patches.

The aim of this study was to prepare self-supporting homogeneous nano/microfibrous layers with a content of the clay mineral kaolinite and kaolinite modified with the antibacterial agent chlorhexidine (CH). Fibers were made of hydrophobic polymers-polyurethane and polycaprolactone. Polymer suspensions for electrospinning contained 2, 5, and 8 wt % (relative to the total weight of the suspension) of kaolinite or CH/kaolinite and were electrospun using 4SPIN LAB. The morphology of prepared fibrous layers was characterized using scanning electron microscopy; energy-dispersive X-ray spectroscopy mapping and Raman spectroscopy were used to confirm the presence and distribution of kaolinite in the layers. Fiber diameters decreased after adding kaolinite or CH/kaolinite and ranged from 600 nm to 5 μm. Antibacterial CH was found in kaolinite itself as well as separately in the fibers (result of imperfect bonding of CH onto the surface of kaolinite). The encapsulation efficiency of all samples exceeded 64%, and the highest efficiency was observed in samples with 2 wt % CH/kaolinite. Samples containing CH exhibited good antibacterial activity against Staphylococcus aureus, and the effectiveness of which was affected by the concentration of the antibacterial agent. The release of CH was very slow, and there was no initial burst release. Overall, no more than 5% of the CH was released over a course of 168 h. The Korsmeyer-Peppas model revealed that CH is released by a diffusion mechanism.

This work concerns the chemical modification of medium molecular weight hyaluronan for ophthalmic applications. The synthesis of amphiphilic HA with dodecanoyl moities was carried out under mild aqueous conditions. Perfect control of the degree of substitution was obtained by varying the molar ratio of activated fatty acid used in the reaction feed. Moreover, the preparation of the derivatives was optimized to achieve the desired degree of substitution (DS = 9.0 ± 0.2 %). The prepared hyaluronan derivatives were water-soluble and exhibited self-associating properties (amphiphilicity). The structure of the prepared derivatives was elucidated by NMR spectroscopy, rheology, turbidity, SEC-MALLS, and gas chromatography (GC). The hydrophobic moieties increase the solution viscosity by physical crosslinking. Low concentration of HAC12 is needed to prepare highly viscous solutions with potential use for ophthalmic applications. Amphiphilic HA kept the biocompatibility of hyaluronan. The degree of substitution and Mw of the amphiphilic HA controls the sterilization by filtration. The protection against desiccation was tested using human keratinocytes (HaCaT) cells lines.

All-trans retinoic acid (ATRA) was grafted to hyaluronan (HA) via esterification. The reaction was mediated by mixed anhydrides. A perfect control of the degree of substitution (0.5-7.5%) was obtained by varying the molar ratio of retinoic acid in the feed. The degree of substitution plays a significant role in the long-term stability. The photodegradation of HA-ATRA upon UVA irradiation resulted in β-ionone, β-cyclocitral and 5,6-epoxy-(E)-retinoic acid. The photostability of the conjugate had increased with the combination with morin. The chemical structure of HA-ATRA and its degradation products was elucidated using NMR spectroscopy, SEC-MALLS, and gas chromatography-mass spectrometry (GC-MS). ATRA did not loss its biological activity after conjugation, as demonstrated by gene expression. The derivative was able to penetrate across the stratum corneum. Besides, HA-ATRA downregulated the expression of anti-inflammatory interleukins 6 and 8. HA-ATRA would be expected to be used for transdermal drug delivery or cosmetics.

In this work, a new amphiphilic derivative made of 10-undecylenic acid grafted to hyaluronan was prepared by mixed anhydrides. The reaction conditions were optimized, and the effect of the molecular weight (Mw), reaction time, and the molar ratio of reagents was explored. Using this methodology, a degree of substitution up to 50% can be obtained. The viscosity of the conjugate can be controlled by varying the substitution degree. The physicochemical characterization of the modified hyaluronan was performed by infrared spectroscopy, Nuclear Magnetic Resonance, Size-Exclusion Chromatography combined with Multiangle Laser Light Scattering (SEC-MALLS), and rheology. The low proton motility and self-aggregation of the amphiphilic conjugate produced overestimation of the degree of substitution. Thus, a novel method using proton NMR was developed. Encapsulation of model hydrophobic guest molecules, coenzyme Q10, curcumin, and α-tocopherol into the micellar core was also investigated by solvent evaporation. HA-UDA amphiphiles were also shown to self-assemble into spherical nanostructures (about 300 nm) in water as established by dynamic light scattering. Furthermore, HA-UDA was crosslinked via radical polymerization mediated by ammonium persulphate (APS/TEMED). The cross-linking was also tested by photo-polymerization catalyzed by Irgacure 2959. The presence of the hydrophobic moiety decreases the swelling degree of the prepared hydrogels compared to methacrylated-HA. Here, we report a novel hybrid hyaluronan (HA) hydrogel system of physically encapsulated active compounds and chemical crosslinking for potential applications in drug delivery.

New method for evaluating the degree of hyaluronan substitution by acyl side groups in the solid state using Raman spectroscopy.

In this work, we report on the preparation of a novel biodegradable textile scaffold made of palmitoyl-hyaluronan (palHA). Monofilament fibres of palHA with a diameter of 120μm were prepared by wet spinning. The wet-spun fibres were subsequently processed into a warp-knitted textile. To find a compromise between swelling in water and degradability of the final textile scaffold, a series of palHA derivatives with different degrees of substitution of the palmitoyl chain was synthesized. Freeze-drying not only provided shape fixation, but also speeded up scaffold degradation in vitro. Fibronectin, fibrinogen, laminin and collagen IV were physically adsorbed on the textile surface to enhance cell adhesion on the material. The highest amount of adsorbed cell-adhesive proteins was achieved with fibronectin (89%), followed by fibrinogen (81%). Finally, textiles modified with fibronectin or fibrinogen both supported the adhesion and proliferation of normal human fibroblasts in vitro, proving to be a useful cellular scaffold for tissue engineering.