International Journal of Pharmaceutics (v.463, #2)

Improved wound dressing: Novel approaches by Alexandru Mihai Grumezescu (117-118).

Polymicrobial wound infections: Pathophysiology and current therapeutic approaches by Serban Bertesteanu; Stefanos Triaridis; Milan Stankovic; Veronica Lazar; Mariana Carmen Chifiriuc; Mihaela Vlad; Raluca Grigore (119-126).
Acute and chronic wounds represent a very common health problem in the entire world. The dermal wounds are colonized by aerobic and anaerobic bacterial and fungal strains, most of them belonging to the resident microbiota of the surrounding skin, oral cavity and gut, or from the external environment, forming polymicrobial communities called biofilms, which are prevalent especially in chronic wounds. A better understanding of the precise mechanisms by which microbial biofilms delay repair processes together with optimizing methods for biofilm detection and prevention may enhance opportunities for chronic wounds healing. The purpose of this minireview is to assess the role of polymicrobial biofilms in the occurrence and evolution of wound infections, as well as the current and future preventive and therapeutic strategies used for the management of polymicrobial wound infections.
Keywords: Wound; Infection; Biofilm; Polymicrobial; Therapy; Vaccination;

Natural and synthetic polymers for wounds and burns dressing by George Dan Mogoşanu; Alexandru Mihai Grumezescu (127-136).
In the last years, health care professionals faced with an increasing number of patients suffering from wounds and burns difficult to treat and heal. During the wound healing process, the dressing protects the injury and contributes to the recovery of dermal and epidermal tissues. Because their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body, some natural polymers such as polysaccharides (alginates, chitin, chitosan, heparin, chondroitin), proteoglycans and proteins (collagen, gelatin, fibrin, keratin, silk fibroin, eggshell membrane) are extensively used in wounds and burns management. Obtained by electrospinning technique, some synthetic polymers like biomimetic extracellular matrix micro/nanoscale fibers based on polyglycolic acid, polylactic acid, polyacrylic acid, poly-ɛ-caprolactone, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, exhibit in vivo and in vitro wound healing properties and enhance re-epithelialization. They provide an optimal microenvironment for cell proliferation, migration and differentiation, due to their biocompatibility, biodegradability, peculiar structure and good mechanical properties. Thus, synthetic polymers are used also in regenerative medicine for cartilage, bone, vascular, nerve and ligament repair and restoration. Biocompatible with fibroblasts and keratinocytes, tissue engineered skin is indicated for regeneration and remodeling of human epidermis and wound healing improving the treatment of severe skin defects or partial-thickness burn injuries.
Keywords: Polymers; Wounds; Burns; Dressing; Extracellular matrix; Regenerative medicine;

All-natural composite wound dressing films of essential oils encapsulated in sodium alginate with antimicrobial properties by Ioannis Liakos; Loris Rizzello; David J. Scurr; Pier Paolo Pompa; Ilker S. Bayer; Athanassia Athanassiou (137-145).
We present natural polymeric composite films made of essential oils (EOs) dispersed in sodium alginate (NaAlg) matrix, with remarkable anti-microbial and anti-fungal properties. Namely, elicriso italic, chamomile blue, cinnamon, lavender, tea tree, peppermint, eucalyptus, lemongrass and lemon oils were encapsulated in the films as potential active substances. Glycerol was used to induce plasticity and surfactants were added to improve the dispersion of EOs in the NaAlg matrix. The topography, chemical composition, mechanical properties, and humidity resistance of the films are presented analytically. Antimicrobial tests were conducted on films containing different percentages of EOs against Escherichia coli bacteria and Candida albicans fungi, and the films were characterized as effective or not. Such diverse types of essential oil-fortified alginate films can find many applications mainly as disposable wound dressings but also in food packaging, medical device protection and disinfection, and indoor air quality improvement materials, to name a few.
Keywords: Antimicrobial wound dressings; Natural materials; Essential oils; Sodium alginate; Surface analysis;

Anionic polymers and 10 nm Fe3O4@UA wound dressings support human foetal stem cells normal development and exhibit great antimicrobial properties by Alexandru Mihai Grumezescu; Alina Maria Holban; Ecaterina Andronescu; George Dan Mogoşanu; Bogdan Stefan Vasile; Mariana Carmen Chifiriuc; Veronica Lazar; Eugen Andrei; Andrei Constantinescu; Horia Maniu (146-154).
The aims of this study were the development, characterization and bioevaluation of a novel biocompatible, resorbable and bio-active wound dressing prototype, based on anionic polymers (sodium alginate – AlgNa, carboximethylcellulose – CMC) and magnetic nanoparticles loaded with usnic acid (Fe3O4@UA). The antimicrobial activity was tested against Staphylococcus aureus grown in biofilms. The biocompatibility testing model included an endothelial cell line from human umbilical vein and human foetal progenitor cells derived from the amniotic fluid, that express a wide spectrum of surface molecules involved in different vascular functions and inflammatory response, and may be used as skin regenerative support. The obtained results demonstrated that CMC/Fe3O4@UA and AlgNa/Fe3O4@UA are exhibiting structural and functional properties that recommend them for further applications in the biomedical field. They could be used alone or coated with different bio-active compounds, such as Fe3O4@UA, for the development of novel, multifunctional porous materials used in tissues regeneration, as antimicrobial substances releasing devices, providing also a mechanical support for the eukaryotic cells adhesion, and exhibiting the advantage of low cytotoxicity on human progenitor cells. The great antimicrobial properties exhibited by the newly synthesized nano-bioactive coatings are recommending them as successful candidates for improving the implanted devices surfaces used in regenerative medicine.
Keywords: Magnetite nanoparticles; Wound dressing; Regenerative medicine; Sodium alginate; Carboximethylcellulose; Human foetal progenitor cells;

Microfluidic one-step synthesis of Fe3O4-chitosan composite particles and their applications by Chih-Hui Yang; Chih-Yu Wang; Keng-Shiang Huang; Chao-Pin Kung; Yi-Ching Chang; Jei-Fu Shaw (155-160).
Schematic of microfluidic emulsification for the production of tadpole-like iron oxide-chitosan composite particles based on the co-precipitation and gelation of a ferro-chitosan solution. Optical image was also illustrated.This paper demonstrates a simple and easy approach for the one-step synthesis of Fe3O4-chitosan composite particles with tadpole-like shape. The length and diameter of the particles were adjustable from 638.3 μm to ca. 798 μm (length), and from 290 μm to 412 μm (diameter) by varying the flow rate of the dispersed phase. Mitoxantrone was used as the model drug in the drug release study. The encapsulation rate of the drug was 71% for chitosan particles, and 69% for magnetic iron oxide-chitosan particles, respectively. The iron oxide-chitosan composite particles had a faster release rate (up to 41.6% at the third hour) than the chitosan particles (about 24.6%). These iron oxide-chitosan composite particles are potentially useful for biomedical applications, such as magnetic responsive drug carriers, magnetic resonance imaging (MRI) enhancers, in the future.
Keywords: Microfluidic droplets; One-step synthesis; Chitosan; Iron oxide; Drug release;

Synthesis and characterization of a novel controlled release zinc oxide/gentamicin–chitosan composite with potential applications in wounds care by Bogdan Stefan Vasile; Ovidiu Oprea; Georgeta Voicu; Anton Ficai; Ecaterina Andronescu; Andrei Teodorescu; Alina Holban (161-169).
Freshly prepared ZnO nanoparticles were incorporated into a chitosan solution in weight ratios ranging from 1:1 to 12:1. Starting from the ratio of 3:1 the chitosan solution was transformed into a gel with a high consistency, which incorporates 15 mL water for only 0.1 g solid substance. The powders obtained after drying the gel were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermal analysis (TG-DSC). The electronic (UV–vis), infrared (FTIR) and photoluminescence (PL) spectra were also recorded. ZnO particles were coated with gentamicin and incorporated into the chitosan matrix, to yield a ZnO/gentamicin–chitosan gel. The release rate of gentamicin was monitored photometrically. This ZnO/gentamicin–chitosan gel proved great antimicrobial properties, inhibiting Staphylococcus aureus and Pseudomonas aeruginosa growth in both planktonic and surface-attached conditions. The results indicate that the obtained composite can be used in cutaneous healing for developing improved wound dressings, which combine the antibacterial activity of all three components with the controlled release of the antibiotic. This wound dressing maintains a moist environment at the wound interface, providing a cooling sensation and soothing effect, while slowly releasing the antibiotic. The system is fully scalable to any other soluble drug, as the entire solution remains trapped in the ZnO–chitosan gel.
Keywords: Zinc oxide; Chitosan; Gentamicin; Controlled release; Improved wound dressing; Antimicrobial effect;

New silica nanostructure for the improved delivery of topical antibiotics used in the treatment of staphylococcal cutaneous infections by Alexandru Mihai Grumezescu; Cristina Daniela Ghitulica; Georgeta Voicu; Keng-Shiang Huang; Chih-Hui Yang; Anton Ficai; Bogdan Stefan Vasile; Valentina Grumezescu; Coralia Bleotu; Mariana Carmen Chifiriuc (170-176).
In this paper, we report the synthesis, characterization (FT-IR, XRD, BET, HR-TEM) and bioevaluation of a novel γ-aminobutiric acid/silica (noted GABA-SiO2 or γ-SiO2) hybrid nanostructure, for the improved release of topical antibiotics, used in the treatment of Staphylococcus aureus infections. GABA-SiO2 showed IR bands which were assigned to Si–O–Si (stretch mode). The XRD pattern showed a broad peak in the range of 18–30° (2θ), indicating an amorphous structure. Based on the BET analysis, estimations about surface area (438.14 m2/g) and pore diameters (4.76 nm) were done. TEM observation reveals that the prepared structure presented homogeneity and an average size of particles not exceeding 10 nm. The prepared nanostructure has significantly improved the anti-staphylococcal activity of bacitracin and kanamycin sulfate, as demonstrated by the drastic decrease of the minimal inhibitory concentration of the respective antibiotics loaded in the GABA-SiO2 nanostructure. These results, correlated with the high biocompatibility of this porous structure, are highlighting the possibility of using this carrier for the local delivery of the antimicrobial substances in lower active doses, thus reducing their cytotoxicity and side-effects.
Keywords: Silica nanopowder; Gamma-aminobutyric acid; Improved MIC; Anti-staphylococcal activity;

Guidance of neural regeneration on the biomimetic nanostructured matrix by Yen-Pei Lu; Chih-Hui Yang; J. Andrew Yeh; Fu Han Ho; Yu-Cheng Ou; Chieh Hsiao Chen; Ming-Yu Lin; Keng-Shiang Huang (177-183).
Directed guidance of neural regeneration and synaptogenesis on the biomimetic nanostructured matrix.Biomimetic materials are used for creating microsystems to control cell growth spatially and elicit specific cellular responses by combining complex biomolecules with nanostructured surfaces. Intercellular cell-to-cell and cell-to-extracellular matrix (ECM) interactions in biomimetic materials have demonstrated potential in the development of drug discovery platforms and regeneration medicine. In this study, we developed a biomimetic nanostructured matrix by using various ECM molecular layers to create a biomimetic and biocompatible environment for realizing neuronal guidance in neural regeneration medicine. Silicon-based substrates possessing nanostructures were modified using different ECM proteins and peptides to develop a biomimetic and biocompatible environment for studying neural behaviors in adhesion, proliferation, and differentiation. The substrates were flat glass, flat silicon wafers (FWs), and nanorod-structured wafers prepared using wet etching. The three substrates were then functionalized using laminin-1 peptide, PA22-2-contained active isoleucine-lysine-valine-alanine-valine (IKVAV) peptide, and poly-d-lysine (PDL), separately. When PC12 cells were cultured and differentiated on the modified substrates, the cells were able to elongate the neurites on the glass and FW, which was coated with three types of peptide. More differentiated neurons were observed on the nanorod-structured wafers coated with laminin than on those coated with IKVAV or PDL. For achieving directional guidance of neurite outgrowth, substrates exhibiting a grating pattern of nanorods were partially collapsed by the pulling force of water, leaving few nanorods, which support the net form of laminin on the surface. Furthermore, we fabricated the topological nanostructure-patterned wafer coated with laminin and successfully manipulated the extension and direction of neurites by using more than 80 μm of a single soma. This approach demonstrates potential as a facile and efficient method for guiding the direction of single axons and for enhancing neurite outgrowth in studies on nerve regenerative medicine.
Keywords: Neural regeneration; Biomimetic; Nanostructure; Extracellular matrix;

Montmorillonite–alginate nanocomposite as a drug delivery system – incorporation and in vitro release of irinotecan by Ruxandra Irina Iliescu; Ecaterina Andronescu; Cristina Daniela Ghitulica; Georgeta Voicu; Anton Ficai; Mihai Hoteteu (184-192).
The scope of the present study was the preparation and characterization of irinotecan nanocomposite beads based on montmorillonite (Mt) and sodium alginate (AL) as drug carriers. After irinotecan (I) incorporation into Mt, the resulting hybrid was compounded with alginate, and I-Mt-AL nanocomposite beads were obtained by ionotropic gelation technique. The structure and surface morphology of the hybrid and composite materials were established by means of X-ray diffraction (XRD), IR spectroscopy (FT-IR), thermal analysis (TG-DTA) and scanning electron microscopy (SEM). Irinotecan incorporation efficiency in Mt and in alginate beads was determined both by UV–vis spectroscopy and thermal analysis and was found to be high. The hybrid and composite materials were tested in vitro in simulated intestinal fluid (pH 7.4, at 37 °C) in order to establish if upon administering the beads at the site of a resected colorectal tumor, the delivery of the drug is sustained and can represent an alternative to the existing systemic chemotherapy. The in vitro drug release test results clearly suggested that Mt, and Mt along with AL were able to control the release of irinotecan by making it sustained, without any burst effect, and by reducing the released amount and the release rate. The nanocomposite beads may be a promising drug delivery system in chemotherapy.
Keywords: Montmorillonite; Alginate; Chemotherapy;

Inhibitory effects of cultured Dendrobium tosaense on atopic dermatitis murine model by Chin-Tung Wu; Keng-Shiang Huang; Chih-Hui Yang; Yu-Chang Chen; Jiunn-Wang Liao; Chao-Lin Kuo; Chung-Li Chen; Shu-Fang Lo; Chang-Chi Hsieh; Hsin-Sheng Tsay (193-200).
Dendrobium tosaense is one of the most valuable Chinese medicines and well developed health food. Atopic dermatitis (AD) is a chronic skin disease that occurs mainly in childhood. The pathogenesis of atopic dermatitis had been studied in BALB/c mice modeling by skin-inoculated ovalbumin (OVA) with 2,4,6-trinitro-1-chrolobenzene (TNCB). These mice exhibit features of chronic dermatitis, including skin rash, mast cells infiltration, and elevated serum anti-OVA specific IgE and cytokines modulation. In this study, a standardized ethyl acetate extract of D. tosaense (DtE) was used to protect these mice from the OVA/TNCB-induced skin lesions of atopic dermatitis. The results indicated an increased population of natural T regulatory cell was accompanied by immunosuppression in cytokine profiles and anti-OVA IgE level to significantly reduce Th2 polarization. Finally, toluidine blue staining indicated mast cell infiltration and degranulation was reduced in skin lesion. Our results were shed light on the usage of D. tosaense in AD.
Keywords: Atopic dermatitis; Dendrobium tosaense; IgE; Mast cell; T regulatory cell;