Co-electrospun-electrosprayed ethyl cellulose-gelatin nanocomposite pH-sensitive membrane for food quality applications.

Anthocyanin from red cabbage is an important biomolecule suitable for pH sensing due to its oxidoreduction potential that leads to a color change at various pH conditions. The pH-sensitive anthocyanin compound was extracted from red cabbage (1785 ± 235 mg/L) and encapsulated with gelatin as the wall material at the nanoscale (350 nm) through electrospraying. By using a simultaneous electrospraying and spinning process at 20 kV, nanoencapsulated anthocyanin was immobilized on ethyl cellulose (EC) nanofibers and formed as a nanocomposite membrane. The surface morphology of developed nanocomposites has shown complex nonwoven nanofiber formation and the immobilized nano encapsulates captured inside the nanofibrous membrane. The pH sensitivity was significantly stable up to 7 days of storage at room temperature. Total color difference has been observed to be statistically significant at different pH conditions of 2 to 12. Also, the application of the nanocomposite strips in pH sensing during milk spoilage was studied and reported.

Thermal oxidation stability of different multi-element oleogels via 1H NMR spectroscopy.

In this study, 1H nuclear magnetic resonance was used to track the evolution of oxidation products of different multi-element oleogels (DMEOs) during temperature-accelerated oxidative degradation. The nutritional properties of the DMEOs were also indirectly explored. Oleogels prepared using sitosterol/lecithin oleogelator showed higher nutritional properties than those prepared using carnauba wax or ethyl cellulose oleogelators. Only a small amount of primary oxidation product hydroxide, (Z,E)-conjugated dienic systems, and (E,E)-conjugated dienic systems were produced from all oleogels upon accelerated oxidation. Furthermore, no 1H signal peaks of secondary oxidation products, such as aldehydes or ketones, were detected. However, very small amounts of primary alcohols (-CH2OH-), secondary alcohols (-CHOH-), and epoxides were identified. Moreover, resveratrol loading and surfactant addition effectively stabilized the internal structure and unsaturated fatty acid acyl content of the oleogels.

Combination of structure-performance and shape-performance relationships for better biphasic release in electrospun Janus fibers.

In nature, the combination of composition, structure, and shape determines the matter's functional performance to a large extent. Inspired by which, two electrospun Janus nanofiber formulations were created using side-by-side electrospinning in this work. Tamoxifen citrate (TAM) was used as a model drug and ethyl cellulose (EC) and polyvinylpyrrolidone K60 (PVP) as the polymer carrier matrices. The fibers have linear cylindrical morphologies and distinct Janus structures by scanning electron microscopy. One side of the fibers took a round shape, while the other was crescent-shaped. The drug was present in both polymer matrices in the form of amorphous solid dispersions, owing to strong intermolecular interactions between drug and polymer. In vitro dissolution tests demonstrated that both sets of fibers could provide biphasic drug release due to the difference in solubility of PVP and EC. The different shape of TAM-EC and TAM-PVP side of the Janus structure resulted in a considerable variation in the drug release profiles. The Janus structure with crescent TAM-PVP side and round TAM-EC side gave a more rapid burst release in the first phase of release, and slower sustained release in the second phase. This work thus reports a new strategy for systematically developing advanced functional nanomaterials based on both shape- and structure-performance relationships.

Characterization of thermo-oxidative behavior of ethylcellulose oleogels.

The thermo-oxidative behavior crucial to the applicability of ethylcellulose (EC) oleogels is characterized. Not only did we take into account the composition of the gel network in relation to textural attributes, but also the dynamic chemical changes occurred during formation, heating, and holding of the gels. EC oleogel oxidative stability showed that at 6.0% EC100 concentration in the oleogels the movement of liquid oil trapped in the gel network was hindered by its high viscosity and stable gel network, thus retarding oxidation. Processing temperature ≤ 120 °C for <2 h was recommended when incorporated in food systems to minimize oxidation. As for the measurement of oxidative stability in general, p-AnV was found suitable in depicting oxidation of EC oleogels. Meanwhile, both Rao and Rad acquired from 1H NMR spectra could serve as reliable oxidative indicators to gauge total oxidation of EC oleogels during storage.

Superhydrophobic three-dimensional porous ethyl cellulose absorbent with micro/nano-scale hierarchical structures for highly efficient removal of oily contaminants from water.

The development of efficient absorbent materials is of global importance for oil spillage cleanup and environmental protection. In this work, a novel superhydrophobic micro/nano-scale hierarchical structured ethyl cellulose sponge was successfully fabricated via an eco-friendly salt-templating method followed by immobilizing silver nanoparticles on the surface and subsequent modification with long-chain alkanethiols. The as-prepared sponge with unique micro-nano structure and porous interconnected network exhibited low density (<17 kg m-3), high porosity (>98%) and robust superhydrophobicity (θwater = 161.3°, θoil = 0°, sliding angle = 3.6°). The sponge could collect a wide range of organic solvents and oils with absorption capacity of 36-48 times of its own weight. Furthermore, the absorption capacity decreased slightly to 89.8% of its initial value after 50 cycles, demonstrating excellent recyclability of the sponge. It was believed that the superhydrophobic/superoleophilic sponge would be a promising absorbent material for the selective oil removal and recovery in environmental remediation.

Supercritical antisolvent co-precipitation of rifampicin and ethyl cellulose.

Rifampicin-loaded submicron-sized particles were prepared through supercritical anti-solvent process using ethyl cellulose as polymeric encapsulating excipient. Ethyl acetate and a mixture of ethyl acetate/dimethyl sulfoxide (70/30 and 85/15) were used as solvents for both drug and polymeric excipient. When ethyl acetate was used, rifampicin was crystallized separately without being embedded within the ethyl cellulose matrix while by using the ethyl acetate/dimethyl sulfoxide mixture, reduced crystallinity of the active ingredient was observed and a simultaneous precipitation of ethyl cellulose and drug was achieved. The effect of solvent/CO2 molar ratio and polymer/drug mass ratio on the co-precipitates morphology and drug loading was investigated. Using the solvent mixture, co-precipitates with particle sizes ranging between 190 and 230nm were obtained with drug loading and drug precipitation yield from respectively 8.5 to 38.5 and 42.4 to 77.2% when decreasing the ethyl cellulose/rifampicin ratio. Results show that the solvent nature and the initial drug concentrations affect morphology and drug precipitation yield of the formulations. In vitro dissolution studies revealed that the release profile of rifampicin was sustained when co-precipitation was carried out with the solvent mixture. It was demonstrated that the drug to polymer ratio influenced amorphous content of the SAS co-precipitates. Differential scanning calorimetry thermograms and infrared spectra revealed that there is neither interaction between rifampicin and the polymer nor degradation of rifampicin during co-precipitation. In addition, stability stress tests on SAS co-precipitates were carried out at 75% relative humidity and room temperature in order to evaluate their physical stability. SAS co-precipitates were X-ray amorphous and remained stable after 6months of storage. The SAS co-precipitation process using a mixture of ethyl acetate/dimethyl sulfoxide demonstrates that this strategy can be successful for controlling rifampicin delivery.

Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation.