Improved properties of incorporated chitosan film with ethyl cellulose microspheres for controlled release

Rheological and radioactive decontamination properties of ethyl cellulose sols in green solvents at a temperature below 0 °C

Strippable film decontamination has been considered one of the best prospects for radioactive surface decontamination due to its high decontamination effect and less secondary pollution. However, research into strippable films has until now focused on radioactive decontamination at room temperature. Therefore, it is vital to seek a suitable degradable material for preparing strippable films in removing contaminants in an extremely cold region, as it will face the problem of the freezing of the detergent. Ethyl cellulose (EC) is a kind of degradable biopolymer which is easily dissolved in volatile green organic solvents to form a sol below 0 °C which is advantageous for forming a film. Therefore, it would be the best choice for preparing a strippable film detergent. In this study, EC sols were obtained by placing EC powder into the green solvents anhydrous ethanol and ethyl acetate. The steady and dynamic rheological behavior of EC sols was investigated with a rotary rheometer with the temperature ranging from -10 °C to 0 °C to disclose their spraying performance. Moreover, the radioactive decontamination effect of EC sols and the mechanism were also investigated. The results showed that the EC sols were pseudoplastic fluids which obeyed the Ostwald-de Waele power law below 0 °C. Furthermore, the viscosity of EC sols could be reduced by stirring, which is convenient for large-area spraying during decontamination below 0 °C. At -10 °C, the comprehensive decontamination rates of all plates were over 85%. Therefore, EC sols could be used as a basic material for strippable film decontamination below 0 °C.

Simple, One-Pot Method for Preparing Transparent Ethyl Cellulose Films with Good Mechanical Properties

In this research, ethyl cellulose films were prepared by a simple, easy, controlled one-pot method using either ethanol or ethyl lactate as solvents, the films being formed at 6 °C. Titanium dioxide nanoparticles were incorporated to improve the oxygen transmission and water vapour transmission rates of the obtained films. This method used no plasticizers, and flexible materials with good mechanical properties were obtained. The resulting solvent-free and transparent ethyl cellulose films exhibited good mechanical properties and unique free-shapable properties. The obtained materials had similar properties to those reported in the literature, where plasticizers were incorporated into ethyl cellulose films with an elastic modulus of 528 MPa. Contact angles showed the hydrophobic nature of all the prepared materials, with contact angles between 80 and 108°. Micrographs showed the smooth surfaces of the prepared samples and porous intersections with honeycomb-like structures. The oxygen and water vapor transmission rates were the lowest for the ethyl cellulose films prepared in ethyl lactate, these being 615 cm³·m⁻²·day⁻¹ and 7.8 gm⁻²·day⁻¹, respectively, showing that the films have promise for food packaging applications.

Fabrication of Flexible pH-Responsive Agarose/Succinoglycan Hydrogels for Controlled Drug Release

Agarose/succinoglycan hydrogels were prepared as pH-responsive drug delivery systems with significantly improved flexibility, thermostability, and porosity compared to agarose gels alone. Agarose/succinoglycan hydrogels were made using agarose and succinoglycan, a polysaccharide directly isolated from Sinorhizobium meliloti. Mechanical and physical properties of agarose/succinoglycan hydrogels were investigated using various instrumental methods such as rheological measurements, attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopic analysis, X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM). The results showed that the agarose/succinoglycan hydrogels became flexible and stable network gels with an improved swelling pattern in basic solution compared to the hard and brittle agarose gel alone. In addition, these hydrogels showed a pH-responsive delivery of ciprofloxacin (CPFX), with a cumulative release of ~41% within 35 h at pH 1.2 and complete release at pH 7.4. Agarose/succinoglycan hydrogels also proved to be non-toxic as a result of the cell cytotoxicity test, suggesting that these hydrogels would be a potential natural biomaterial for biomedical applications such as various drug delivery system and cell culture scaffolds.

Preparation and characterization of ethyl cellulose film modified with capsaicin

Pure ethyl cellulose film cannot extend the shelf life of food, and adding capsaicin as an antibacterial agent can inhibit the activity of microorganisms on the surface of the film. The main purpose of this work is to study the properties and specific performance of the film formed by adding capsaicin to ethyl cellulose system. Importantly, the transparent, soft, and stretchable ethyl cellulose-capsaicin composite membrane (EC-Cap) is generally easy to produce and is environmentally friendly. It is the first successful preparation by a casting method. It is worth noting that the FTIR analysis of the film shows that there may be an interaction between the phenolic hydroxyl group in Cap and the hydroxyl group in EC, which means that Cap has successfully participated in the film formation system. Therefore, the cap-containing film not only exhibits a low water absorption, when the cap is appropriate, the elongation at break of the film reaches a maximum of 61.34 % ± 1.37 %. Compared with pure EC membrane, EC-Cap membrane has greater antibacterial activity than pure EC membrane. The practical application of EC-Cap films in the protection of bell peppers has shown positive results, which makes it possible to apply these films to food packaging.

Preparation of Ethyl Cellulose Microspheres for Sustained Release of Sodium Bicarbonate

Sustained release of thermal-instable and water-soluble drugs with low molecule weight is a challenge. In this study, sodium bicarbonate was encapsulated in ethyl cellulose microspheres by a novel solid-in-oil-in-oil (S/O/O) emulsification method using acetonitrile/soybean oil as new solvent pairs. Properties of the microspheres such as size, recovery rate, morphology, drug content, and drug release behavior were evaluated to investigate the suitable preparation techniques. In the case of that the ratio of the internal and external oil phase was 1: 9, Tween 80 as a stabilizer resulted in the highest drug content (2.68%) and a good spherical shape of microspheres. After the ratio increased to 1: 4, the microspheres using Tween 80 as the stabilizer also had high drug content (1.96%) and exhibited a sustained release behavior, with 70% of drug released within 12 h and a sustained release of more than 40 h. Otherwise, different emulsification temperatures at which acetonitrile was evaporated could influence the drug release behaviour of microspheres obtained. This novel method is a potential and effective method to achieve the encapsulation and the sustained release of thermal-instable and water-soluble drugs with low molecule weight.

Design and biological response of doxycycline loaded chitosan microparticles for periodontal disease treatment

The aim of this study was to develop chitosan (CS) microparticulated mucoadhesive drug delivery system (DDS) with improved therapeutic performance and biological responce. Ionotropic gelation/spray drying process was used for preparation of doxycycline hyclate (DOXY) loaded low and medium molecular weight (LMw and MMw) CS/sodium tripolyphosphate microparticles (CS/TPP MPs), further coated with ethyl cellulose (EC) using coacervation/solvent displacement technique. The relevant physico-chemical and biopharmaceutical properties were optimized using experimental design approach. Both coated and uncoated CS/TPP MPs showed high mucoadhesive potential and did not affect the viability of the tested epithelial cell line. The MPs induced slow and gradual apoptotic response in murine macrophage cell line RAW 264.7 and the observed effect depended upon formulation type and MP concentration. Biological effect of the CS-based MPs observed in our experiments point to synergism of the biological response of the carrier with the anti-inflammatory effect of DOXY.

SYNTHESIS AND CHARACTERISATION OF ELECTROSPUN CHITOSAN MEMBRANES REINFORCED BY HALLOYSITE NANOTUBES

We report on the electrospinning method to synthesize and characterise chitosan membranes reinforced by halloysite nanotubes (HNTs). The synthesis process addressed two levels of HNTs concentration, i.e., 2 and 5 wt.%. Tensile testing was carried out to determine the strength (σ), strain (ε) at σ and elastic modulus (E) of the membranes. Tensile test data revealed that the membranes reinforced with 5 wt.% HNTs yielded the highest E (0.153 ± 0.02 GPa) and strength (22.53 ± 8.57 MPa). Electron micrographs of the fractured surfaces showed uniform dispersions of HNTs in the chitosan matrix. Infrared spectra indicated interactions between chitosan and inner and outer surfaces of HNTs. Thermogravimetric analysis demonstrated an increase in thermal stability with the addition of HNTs. Membranes immersed in simulated body fluid system for 28 days revealed the formation of dense apatite blocks with the addition of HNTs. Surface roughness increased with the addition of HNTs resulted a rise in degree of contact angle.

Chitosan films: crosslinking with EDTA modifies physicochemical and mechanical properties

The present study was aimed to develop chitosan-EDTA films and evaluate their physico-chemical and mechanical properties. The physical properties suggested lowest swelling, volume and volume index of films prepared by employing equal weight of chitosan (CH) and EDTA (1.5% w/v). The CH:EDTA film (1:l, on weight basis) showed minimum contact angle, work of adhesion and high negative spreading coefficient indicating lipophilic behavior of film. Further, the FTIR and DSC analysis suggested maximum crosslinking density in film prepared with equal proportion of CH and EDTA. The mechanical properties explored using texture analyzer revealed increasing the proportions of EDTA rendered the films more flexible and decreased their hardness. Furthermore, in vitro permeation of 5-FU and mesalamine with different solubilities showed minimum permeation across CH–EDTA (1:1) film, indicating high crosslinking density that decreased void space inside the film. Hence, the CH–EDTA conjugate could be considered to be possess great potential for various pharmaceutical applications such as film based delivery systems, controlled and sustained delivery systems etc.

Smart nanocontainers as depot media for feedback active coatings

Among the grand challenges at present are ways to develop systems with low consumption of raw materials and with little load on the environment. In view of this it is of utmost importance to avoid or to delay processes causing material destruction. This is especially urgent, since many protective substances have associated health hazards, and new routes to improve the situation are a main concern of this contribution. Nanocapsules (nanocontainers) with controlled release properties of the shell can be used to fabricate a new family of active coatings, with quick response to changes of the coating environment or coating integrity. The release of active materials encapsulated into nanocapsules is triggered by various external and internal factors, thus preventing spontaneous leakage of the active component. The coating can have several active functionalities when several types of nanocapsules loaded with corresponding active agent are incorporated simultaneously into a coating matrix. We highlight recent achievements in development and application of filled responsive containers in biomedical and self-healing protective coatings.

Co-delivery of doxorubicin and plasmid by a novel FGFR-mediated cationic liposome

In our previous study, we developed a novel cationic liposome, which was modified with truncated human basic fibroblast growth factor (tbFGF) peptide. This tbFGF-mediated cationic liposome could deliver chemotherapeutic agents or gene specifically to FGFRs on tumors and obtained higher transfection efficiency than plain cationic liposomes. In order to investigate whether this novel cationic liposome could achieve a synergistic/combined anti-tumor effect as a co-delivery system, we simultaneously delivered doxorubicin (DOX) and the plasmid encoding the phosphorylation-defective mouse survivin threonine 34-->alanine mutant (Msurvivin T34A plasmid) to the same cells through this cationic liposome. As a result, an enhanced antiproliferative activity in vitro has been achieved by delivering DOX and DNA simultaneously to the Lewis lung carcinoma cells (LLC) using this liposome. The concentration of DOX in the co-delivery system which caused 50% killing was nearly 3-fold lower than that of the free DOX. Furthermore, the co-delivery system suppressed tumor growth more efficiently than either DOX or the Msurvivin T34A plasmid alone in the Lewis lung carcinoma-bearing C57BL/6 mice. After 18 days of treatment with the co-delivery system, the average tumor volume in mice was decreased by 80%, which was higher than liposomal DOX (70%, P<0.05) and Msurvivin T34A plasmid (41%, P<0.01). The co-delivery system also caused 15 days delay of tumor growth, which was longer than the other treatment groups. In conclusion, this novel cationic liposome is an efficient vector to simultaneously deliver drugs and DNA to the same cells in vitro and in vivo.