Ethylcellulose Matrix Research Articles

Emission based response of Er3+, Tb3+, and Er3+-Tb3+ co-doped 1393 bioactive glasses along with HPTS towards CO2

The HPTS serves as a versatile tool in pH and CO2 sensing studies, as well as in cell biology studies of various processes. However, the long-term photostability of HPTS as a fluorescent dye is an important consideration in its use, especially for long-term applications. In this work, sol–gel synthesized Er3+, Tb3+ and Er3+: Tb3+ co-doped 1393 bioactive glass particles were incorporated with the HPTS in the presence of ionic liquid in an ethyl cellulose matrix. The interaction of the bioactive glasses with the HPTS was investigated by steady-state luminescence and excited-state lifetime measurements. The prepared composites showed linearizable responses when exposed to different CO2 concentrations. High I0/I100 values (87, 109 and 115) were obtained for the binary blends of HPTS and bioactive glasses. When the imidazolium-based IL was used together with the offered composites, we observed improved stability and longevity for the HPTS up to 315 days. The incorporation of imidazolium-based ionic liquids as additives in HPTS-based fluorescence assays together with the bioactive glasses holds promise for enhancing the photostability of the HPTS and improving the reliability and longevity of fluorescence signals in various research applications.

Bioactive Ag(I) coordination complexes as dopants for castor oil plasticized ethylcellulose films.

The effects exerted by new bioactive acylpyrazolonate Ag(I) derivatives of the general formula [Ag(QPy,CF3)(R-Im)] containing different substituents on the imidazole (R-Im) ancillary ligands and the natural plasticizer castor oil when both are added to the ethylcellulose (EC) biopolymer in the preparation of thin films as potential active food packaging materials are presented. The Ag(I) complexes [Ag(QPy,CF3)(Bn-Im)] and [Ag(QPy,CF3)(Bu-Im)], having benzyl and butyl substituents, whose single crystal molecular structures are reported, have proved to be highly compatible for efficient incorporation between the EC polymer and the hydrophobic plasticizer chains, giving rise, even at low concentrations, to homogeneous, robust and elastic films. The concomitant presence of these Ag(I) complexes and castor oil in the polymer EC matrix gives rise to thin films with improved antibacterial activity against Escherichia coli (E. coli) as a model of Gram-negative bacterial strains when compared to the non-plasticized ones, with very low Ag(I) migration in the three food simulants used (distilled water, ethanol 10% v/v and acetic acid 3% v/v) under two assay conditions (70 °C for 2 h and 40 °C for 10 days).

Ethyl cellulose/carbonized spent coffee ground-based biocomposites for superior hydrophobicity and electric protection performance

Endowing naturally-derived electric protection materials with hydrophobicity is required to guarantee their service reliability under harsh environments and eco-friendly disposal. Herein, a conductive biocomposite was designed and fabricated using a melt-processable ethyl cellulose (EC) matrix, and a carbonized spent coffee ground (CSCG) filler with a nitrogen-doped sp2 hybridized carbon structure. In terms of functional groups, defects, and crystal structure, CSCG prepared at 1000 °C was the best suited for improving the electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of the fabricated composites. The EC composite containing 70 wt% CSCG prepared at 1000 °C exhibited an electrical conductivity of 6.79 × 101 S/m, an EMI SE/thickness of 13.2 dB/mm, and a water contact angle of ∼ 104°. Therefore, the material design strategy used in this study can provide insight into the development of naturally-derived electric protection materials with hydrophobicity.

Ethyl cellulose–graphene oxide composite dense membranes: Kinetic and thermodynamic studies of dye adsorption

Graphene oxide (GO) is extensively used in dye adsorption from wastewater. Polymer–GO composite membranes exhibits improved surface wettability and dye adsorption capacity. In this study, ethyl cellulose (EC)–GO nanocomposite dense membranes (EG membranes) are prepared by the solvent casting method. The morphology and physicochemical properties of the developed nanocomposite membranes are characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction studies, thermogravimetric analysis, static contact angle measurements, and UV–visible spectroscopy. The derivative thermogravimetry curves indicate the complete degradation of the composites below [Formula: see text]C. The results confirm the homogeneous dispersion of GO in the EC matrix. The addition of GO to the EC matrix leads to a remarkable increase in surface wettability which decreases the contact angle to [Formula: see text] for the membrane with a 0.7% addition of GO. The prepared membranes are used for the separation of methylene blue from water. The adsorption properties of the prepared membranes are found to be varying in accordance with the contact angle values. The equilibrium data fit well for the Langmuir model and the adsorption follows pseudo-second-order kinetics.

GR-Fe3O4/PLA 3D printing composite materials with excellent microwave absorption properties

In this work, composite microspheres were formed by integrating graphene (GR) and Fe3O4 into an ethylcellulose matrix via an emulsion emulsification reaction. Composite wires were fabricated using a melt extrusion process and composite samples were subsequently prepared via a melt molding method. A systematic study was conducted to investigate the absorption performance of GR-Fe3O4/PLA (Polylactic acid) composite materials. The findings revealed that the optimal microwave absorption performance was achieved when the graphene content was 5.6 wt% and the Fe3O4 content was 11.1 wt%. The maximum reflection loss was − 51.13 dB at a thickness of 2.65 mm. The maximum absorption bandwidth was 4.16 GHz, and the effective radar interception cross-section was reduced to − 42.7 dBm2. The excellent performance of GR-Fe3O4/PLA composite material can be attributed to good impedance matching and the synergistic effect of conductive loss, dipole polarization, interface polarization, and eddy current loss. Then the contribution of conductive loss and polarization loss to the absorption performance was explored. This work provides a novel approach to advance the design and development of functional materials for efficient electromagnetic absorption, providing valuable insights into the development of efficient, lightweight microwave absorbing material.

EFFECT OF PREPARATION TEMPERATURE ON ETHYLCELLULOSE MICROSPHERE PROPERTIES PREPARED BY OIL-IN-OIL EMULSION SOLVENT EVAPORATION PROCESS

The present study aims to formulate ethylcellulose microspheres using the oil-in-oil emulsion solvent evaporation method and judge the outcome of processing temperature on their features. The effects of the evaporation rate of the solvent on the particle properties and drug release characteristics of the microspheres were studied. Here, microspheres were prepared at different processing temperatues, viz., 10 0 C, 25 0 C, and 40 0 C, and their impact on the various characteristics of microspheres like surface topography, micrometrics, yield percent, encapsulation efficiency, in vitro dissolution, Fourier-transform infrared spectroscopy (FTIR) and release kinetics were elaborately studied. The FTIR study revealed that processing temperature did not affect drug-polymer compatibility. The study observed that the processing temperature had a great influence on the various characteristics of the prepared microsphere. It was observed from sieve analysis that the mean particle size of the microsphere increased with an increase in processing temperature, and the SEM study also corroborated the same result. SEM photographs showed processing at a higher temperature resulted in particles with a smooth surface, in contrast to a lower processing temperature that forms a bumpy surface. Furthermore, a higher temperature favoured formulation with a higher entrapment efficiency (94.42 ± 0.9 %) as compared to a lower temperature (85.2 ± 0.72 %). For a noteworthy timeframe, indinavir sulfate frames a solid solution in the ethylcellulose matrix and proceeds with the amorphous state. The results of an in vitro drug dissolution study showed that microspheres formulated at a higher temperature had a more sustaining effect as compared to those formulated at a lower temperature, which may have resulted due to their higher mean particle size. Using the Korsemeyer Peppas power law, it was found that the way drugs are released is controlled by diffusion.

Preparation of sorbents for solid-phase extraction of benzoic acid from aqueous solutions

Aim to obtain sorbents based on ethylcellulose for solid-phase extraction of benzoic acid from aqueous solutions.
 Material and methods. To create the sorbents for solid-phase extraction, we used the following reagents: ethyl cellulose, copper sulfate pentahydrate, sodium hydroxide, benzoic acid, purified water, ethyl alcohol 95%. The samples of ethyl cellulose-based sorbents were studied by Fourier transform IR spectrometry on an Agilent Cary 630 FTIR spectrometer. The Agilent Microlab PC Expert software was used for registration and primary processing of IR spectra, and for statistical analysis. The capacity of sorbents for solid-phase extraction was evaluated in a dynamic mode. The microstructure of the samples was studied by field emission scanning electron microscopy (FE-SEM) on a Hitachi SU8000 electron microscope. The specific surface area of the synthesized sorbents was measured by low-temperature nitrogen porometry using the Brunauer Emmett Teller approximation, on the Autosorb 1 device, using the Quantachrome AS1Win software, according to a well-known technique.
 Results. А method was proposed for obtaining a sorbent for solid-phase extraction of benzoic acid from aqueous solutions. The IR-spectrometry did not reveal significant differences between ethylcellulose samples and the obtained sorbent samples. The optimal concentrations of ethylcellulose and benzoic acid in the reaction mixture were determined to create a sorbent with a maximum capacity of 19.2 g/g. The differences in the morphological structure of the surface of ethylcellulose matrix and obtained sorbents were described. The specific surface area of ethylcellulose sorbent with a maximum capacity for benzoic acid was 14.10 cm2/g.

Ratiometric optical oxygen sensor based on perovskite quantum dots and Rh110 embedded in an ethyl cellulose matrix

Ratiometric optical sensor gas sensing continues to develop optical sensing techniques and materials used in various industrial and environmental applications. This research focuses on a new ratiometric optical sensor using the development of new material of FAPbI3 perovskite QDs and a simple method to detect oxygen (O2) gas. FAPbI3 perovskite QDs are used as an indicator of oxygen gas, and rhodamine 110 (Rh 110) is a reference material in a ratiometric optical sensor. All of the sensing and reference materials are embedded in an ethyl cellulose (EC) matrix and coated on the surface of the filter paper. Using a UV LED with a central wavelength of 380 nm as the excitation light source, the emission spectra results show that the emission wavelengths of the oxygen-sensitive dye (O2) FAPbI3 perovskite QDs do not overlap with the Rh 110 reference signal. Thus, oxygen concentration can be measured using a ratiometric fluorescence reference-based approach. The sensing signal will be obtained in the presence of analyte gas in the ratiometric sensitivity of R0/R100, where R0 and R100 represent the luminescence intensity detected in 100% nitrogen and 100% oxygen concentrations, respectively. The experimental results show the optical oxygen sensor's sensitivity as R0/R100 = 12.7. In addition, the response time and recovery of the oxygen gas sensor produced are 75 s and 93 s, respectively. The use of a new type of FAPbI3 perovskite QDs material has been successfully developed in the optical ratiometric sensor for oxygen gas. The sensor proposed in this study has a low cost and easy fabrication process. The effect of spurious fluctuations in the excitation source intensity can be suppressed by the ratiometric optical sensing method.

Modulation of the oxygen sensing properties of iridium (III) complexes by changing their substitution groups

In this study, new bis-cyclometalated iridium (III) complexes bearing different ligated groups (–H, –OCH3, –F, –CH3) at the aryl moiety (Ir-1, Ir-2, Ir-3 and Ir-4) were synthesized and characterized. Then oxygen sensing properties of corresponding complexes were investigated in EC film. The complexes showed room temperature phosphorescence spectra in the range of 562–590 nm in THF and 546–554 nm in ethyl cellulose (EC) matrix. When they were incorporated in an ethyl cellulose matrix, the probes showed optimal dynamics of luminescence for oxygen monitoring in the range from 0 % to 100 % air saturation. The I0/I100 values of Ir-1, Ir-2, Ir-3 and Ir-4 in EC thin film were calculated as 10.9, 5.0, 7.3 and 22.7, respectively. The results showed that the oxygen sensitivity accomplishment of the complex core can be fine-tuned by varying these ligated groups, and the weak electron-donating properties of the methyl groups at the aryl moiety improve remarkably the optical oxygen sensing abilities of the Iridium (III) complexes.

Investigating the Potential of Ethyl Cellulose and a Porosity-Increasing Agent as a Carrier System for the Formulation of Amorphous Solid Dispersions.

In the present work, an insoluble polymer, i.e., ethyl cellulose (EC), was combined with the water-soluble polyvinylpyrrolidone (PVP) as a carrier system for the formulation of amorphous solid dispersions. The rationale was that by conjoining these two different types of carriers a more gradual drug release could be created with less risk for precipitation. Our initial hypothesis was that upon contact with the dissolution medium, PVP would be released, creating a porous EC matrix through which the model drug indomethacin could diffuse. On the basis of observations of EC as a coating material, the effect of the molecular weight of PVP, and the ratio of EC/PVP on the miscibility of the polymer blend, the solid state of the solid dispersion and the drug release from these solid dispersions were investigated. X-ray powder diffraction, modulated differential scanning calorimetry, and solid-state nuclear magnetic resonance were used to unravel the miscibility and solid-state properties of these blends and solid dispersions. Solid-state nuclear magnetic resonance appeared to be a crucial technique for this aspect as modulated differential scanning calorimetry was not sufficient to grasp the complex phase behavior of these systems. Both EC/PVP K12 and EC/PVP K25 blends were miscible over the entire composition range, and addition of indomethacin did not alter this. Concerning the drug release, it was initially thought that more PVP would lead to faster drug release with a higher probability that all of the drug molecules would be able to diffuse out of the EC network as more pores would be created. However, this view on the release mechanism appeared to be too simplistic as an optimum was observed for both blends. On the basis of this work, it could be concluded that drug release from this complex ternary system was affected not only by the ratio of EC/PVP and the molecular weight of PVP but also by interactions between the three components, the wettability of the formulations, and the viscosity layer that was created around the particles.

Development of TiO2 photocatalyzed EC/HTPB based oxygen scavenging mats by electrospinning method for packaging applications

In this work, oxygen absorption properties of titanium dioxide (TiO2) photocatalyzed ethyl cellulose (EC)/hydroxyl terminated polybutadiene (HTPB) blends have been studied. Oxygen scavenging samples were prepared using solution casting and electrospinning methods from two different binary mixtures, toluene/ethanol and ethanol/water, respectively. Morphological observations for electrospun mats confirmed that the addition of HTPB to EC matrix increased the tendency of the mixture to obtain a smooth fibrous structure compared to that of pure EC. Viscosity and FTIR-ATR measurements were carried out to study the stability and homogeneity of the blends in ethanol/water mixture. Applicability of Cox-Merz empirical rule led us to believe that catalyzed electrospinning blend was homogenous. A similar ratio of EC to HTPB in electrospun mats prepared in ethanol/water compared to the one prepared in toluene/ethanol is shown by FTIR-ATR spectra, which revealed the stability of the blends in this mixture. The oxygen absorption measurements depicted significant oxygen absorption capacity for cast films and electrospun mats which could reach about the averages of 54 cm3 (25 °C, 1013 hPa)/g and 59 cm3 (25 °C, 1013 hPa)/g, respectively, after 30 days. The oxygen scavenging capacity of electrospun mats was higher than cast films as a result of the higher surface area in the fibrous structure.

Improvement of optical properties of one-dimensional CaAl12O19:Mn4+ phosphor via Er3+- and Tb3+- doped bioactive glass powders

Until now, because of the being a candidate for the red-emitting material the CaAl 12 O 19 :Mn 4+ phosphor (CAO:Mn) has been widely used especially in white light-emitting diodes (WLEDs). In this study, the emission-based luminescence properties of CaAl 12 O 19 :Mn 4+ red phosphor synthesized via sol-gel method was studied in the absence and presence of Er 3+ - and Tb 3+ -doped 13–93 bioactive glass powders in ethyl cellulose (EC) matrix in detail. Upon the addition of un-doped and Er 3+ - and Tb 3+ - doped bioactive glass powders, the CAO:Mn phosphor resulted in 44%, 92% and 88% increase in the emission intensity, respectively. The luminescence and decay time characteristics of the synthesized phosphor were also investigated in terms of microsecond time scale. The proposed material may bring a new inside for the existing problems of the red phosphors regarding the brightness, colour correlation temperature and colour rendering index. • The optical properties of the CaAl 12 O 19 :Mn 4+ (CAO:Mn) along with Er 3+ - and Tb 3+ - doped bioactive glass powders were evaluated. • The intensity CAO:Mn; has been enhanced along with 1% Er 3+ - and 5% Tb 3+ - doped bioactive glass powders up to 92% and 88%, respectively. • The improvement in the efficiency of the phosphor has been performed by a cost-effective way.

Role of release modifiers to modulate drug release from fused deposition modelling (FDM) 3D printed tablets

Although hot melt extrusion (HME) has been used in combination with fused deposition modelling (FDM) three-dimensional printing (3DP), suitable feedstock materials such as polymeric filaments with optimum properties are still limited. In this study, various release modifying excipients, namely, poly(vinyl alcohol) (PVA), Soluplus®, polyethylene glycol (PEG) 6000, Eudragit® RL PO/RS PO, hydroxypropyl methylcellulose (HPMC) K4M/E10M/K100M, Kollidon® vinyl acetate 64 (VA 64)/17PF/30, were used as a release modulating tool to control the drug release from 3D printed sustained release tablets. Ibuprofen (as the model drug) and ethyl cellulose (as the polymeric matrix), along with various release modifiers, were blended and extruded into filaments through a twin-screw extruder. Then these filaments were printed into cylindrical tablets through FDM 3DP technique and their surface morphology, thermal stability, solid-state, mechanical properties, dose accuracy and drug release behaviors were investigated. The solid-state analysis of 3D printed tablets exhibited the amorphous nature of the drug dispersed in the polymer matrices. Although all these prepared filaments could be successfully printed without failing during the FDM 3DP process, the mechanical characterization showed that the filament stiffness and brittleness could be adjusted significantly by changing the type of release modifiers. Moreover, in vitro drug release studies revealed that the drug release could simply be controlled over 24 h by only changing the type of release modifiers. All ibuprofen (IBP) loaded 3D printed tablets with ethyl cellulose (EC) matrix, especially with PEG as the release modifier, showed great potential in releasing IBP in a zero-order reaction. In conclusion, all the results illustrated that the HME/FDM approach and optimized formulation compositions can be an attractive option for the development of pharmaceutical tablets and implants where adjustable drug release patterns are necessary.

Magnetic amendment in the fabrication of environment friendly and biodegradable iron oxide/ethyl cellulose nanocomposite membrane via electrospinning

Organic and inorganic composite nanomaterials have been extensively investigated for diverse magnetic applications. However, the rigidity of the nanoparticles hinders their practical implementation. In this study, an environmentally benign composite flexible nanofiber membrane containing magnetic α-Fe2O3 nanoparticles and ethyl cellulose was fabricated by electrospinning. X-ray diffraction, FTIR, SEM and TEM investigated the structural properties systematically while VSM analysis was used to compare the magnetic properties of α-Fe2O3 and α-Fe2O3/C20H38O11 nanomaterials. XRD patterns exhibit all characteristics of the diffraction peaks of synthesized samples without any secondary phase. Sharp peaks were observed in FTIR spectral characteristic bands evince that absorption band becomes more prominent for α-Fe2O3/ethyl cellulose nanocomposite than pristine ethyl cellulose. SEM analysis reveals the homogenous growth of particles and uniformly, dense pattern of nanofiber membrane. TEM image demonstrates the complete dispersion of α-Fe2O3 nanoparticles within the ethyl cellulose matrix. The enhanced values of remnant and saturated magnetization of the α-Fe2O3/C20H38O11 nanofiber membrane exhibits the imperative role of nanocomposite in the flexible applications. In this work, α-Fe2O3 nanoparticles were synthesized with the help of hydrothermal method and electrospinning was used to fabricate α-Fe2O3/C20H38O11 nanofiber membrane. The crystallite size calculated for α-Fe2O3 nanoparticle prepared by hydrothermal process is relatively larger than that for nanoparticles embedded within the α-Fe2O3/C20H38O11 nanofiber membrane. Significant decrease in the agglomeration of α-Fe2O3 nanoparticles within nanofiber membrane accounted for its enhanced the magnetic properties.

Synthesis, characterization and oxygen sensitivity of cyclophosphazene equipped-iridium (III) complexes.

In this work, synthesis, characterization and oxygen sensing abilities of the cyclophosphazene-free and phenyl and naphtoxy-substituted cyclophosphazene bearing iridium (III) complexes (Ir-I, Ir-II and Ir-III) were presented. The complexes were characterized by NMR, absorption and emission spectroscopies, luminescence lifetime and quantum yield measurements. The molecules were successfully embedded in the ethyl cellulose matrix to fabricate the oxygen sensing electrospun mats via electrospinning technique. Oxygen induced luminescence of the iridium complexes around 600nm has been followed as the analytical signal during oxygen sensitivity studies. They exhibited blue shifted, quenched emission towards triplet oxygen. The napthoxy substituted derivative exhibited 2.70 fold enhanced I0/I100 ratio compared to the free form in terms of the relative signal change. Room-temperature luminescence abilities, high photostabilities, large Stoke's shift values extending to 200nm and high spectral response, especially between 0 and 10% pO2 make them promising candidates as oxygen probes. The test materials can be stored at the ambient air of the laboratory for at least 24months.

Printable Colorimetric Sensors for the Detection of Formaldehyde in Ambient Air

Introduction With an annual production of 21 million tons [1], formaldehyde (CH2O) is probably one of the most produced chemicals worldwide. It serves as starting material for many other industrially produced chemicals, but also the demand of its pure form is steadily rising. In nature, CH2O originates i.a. endogenously as intermediate of metabolism in most living systems [2], however chronic exposure poses a high risk to humans’ health. In June 2014, the European Union reclassified the toxicological properties of CH2O in its regulation 605/2014, as carcinogen (category 1B) and mutagen (category 2) [3]. Despite its high toxicity, but due to its disinfecting, germicidal and preserving properties, the usage of CH2O is common in the production of many everyday objects like for example adhesives, furniture, coatings, cosmetics and textile finishing. Thus, CH2O is not only a risk to workers of processing industries, but it is also becoming important for the assessment of indoor air quality, increasingly.Within the scope of our research, we present a simple method to monitor CH2O in ambient air based on a visible color change of a disposable sensor, which can be evaluated using the camera of a smartphone or even naked eye. Figure 1a illustrates the sensor principle. The sensor consists of a paper/plastic substrate on which the gas sensitive material is deposited by printing process. The integration of the gas sensitive layer into a defined QR code pattern realizes quantitative as well as an illumination and camera independent evaluation of the color change due to the contact with the target gas. To protect the gas sensitive material and the color reference against environmental influences, the sensor is packed gas-tight.Focus of this work is on the development of printable pastes based on the reaction of a primary amine with CH2O through nucleophilic addition, which takes place under change of basicity. One method, to track this chemical reaction with conventional pH indicators, and the adaption to the later scope by the choice of pH indicator is discussed. Figure 1b shows the reaction scheme by the example of the pH indicator bromocresol green. Method Starting with a white poly(p-phenylene oxide) (PPE) coated matte paper, pastes were developed for the deposition of the gas sensitive material by screen-printing. The color reference was printed by UV offset in advance. For the preparation of printable pastes, the pH indicators and the primary amine were dissolved in ethanol and embedded into an ethyl cellulose matrix (ethoxyl content 48%, ALDRICH Chemistry, USA) using tributyl phosphate (≥99.0%, SIGMA-ALDRICH, USA) as plasticizer. Furthermore, aids to support the printing process, the layer and the color formation were investigated. Two primary amines in combination with eight pH indicators (bromophenol blue, bromocresol green, methyl red, bromophenol red, bromocresol purple, bromothymol blue, phenol red and phenolphthalein) with transition ranges pH 3.0-12.0 were examined. The color change was characterized by UV/Vis spectroscopy (Lambda900, Perkin-Elmer, USA) with a setup for diffuse reflection (Praying Mantis, Harrick Scientific Products Inc., USA) as well as the by the evaluation of RGB values taken with an in-situ readout station using the camera of an iPhone 6s. General description of the used gas measurement station is given in [4]. The printed sensors were characterized to CH2O concentrations between 100 ppb to 10 ppm. Furthermore, cross-sensitivities to humidity and other interfering gases with focus on ammonia were examined. Results and Conclusions Our research evaluates and compares eight pH indicators, to monitor CH2O by the reaction with a primary amine, regarding sensitivity and selectivity.Figure 1c shows the reflection spectra of a printed gas sensitive layer to 4 ppm CH2O by the example of the pH indicator bromocresol purple. The measurement consists of 15 spectra recorded in intervals of two minutes. CH2O was exposed for 20 minutes, before and afterwards the gas measurement chamber was flushed with synthetic air for five minutes, respectively. After exposure to the target gas, a complete color change from blue to yellow occurred (see Figure 1d).Based on this evaluation and adaption of the printing parameters, the integration time of the sensors can be adjusted to the later target range e.g. to a working day of eight hours or a short-term measurement of 15 minutes and the gas concentration range.

Use of cellulose acetate butyrate as a carrier for preparation of alcohol-resistant matrix tablet

The objective of this study was to investigate cellulose acetate butyrate (CAB) as a carrier for extended-release alcohol-resistant matrix tablet. Powder blends were either directly compressed or granulated before compression. The drug release from CAB matrix tablet was robust to formulation/process parameters such as compression force (10−20 kN), granular size (0.15−1.40 mm), and drug content (50–70%). In addition, release medium variables such as ionic strength, pH, and agitation rate had no effect on the drug release. CAB matrix tablet was more robust than ethylcellulose matrix tablet; the release from CAB matrix tablet was not affected by ethanol content (up to 20% v/v) in the release medium irrespective of agitation. CAB is a promising polymer for formulating of alcohol-resistant extended-release matrix tablet.

Preparation and Characterization of Silver(I) Ethylcellulose Thin Films as Potential Food Packaging Materials.

Ag(I)-containing ethylcellulose (EC) films suitable as antbacterial packaging materials have been prepared and fully characterized. Different preparation methods, including the use of green casting solvents, are proposed. The Ag(I) acylpyrazolonato complexes, [Ag(Qpy,CF3 )(L)], L=benzylimidazole (Bzim) and L=ethylimidazole (EtimH), used as active additives, display different modes of interactions with EC, depending on their structural features. A thorough investigation of the EC liquid-crystalline lyotropic phase and its changes with the introduction of silver additives, has been conducted, revealing either the inclusion of complex molecules into the inner structure of the EC matrix or their dispersion on its surface. Moreover, the bactericidal activity of the prepared Ag(I) films seems to be related to the interaction between silver additives and the polymeric EC matrix. Indeed, the EC-2b films show a particularly good performance even with a low silver content, with a relative bacterial killing of about 100 %. Tests for Ag(I) migration have been performed by using three food stimulants under two assay conditions. Low values of silver release are recorded, particularly at low concentration of silver content, in the case of all new prepared Ag(I) films.

Development of highly sensitive [Ru(bpy)3]2+ - Based optical oxygen sensing thin films in the presence with Fe3O4 and Fe3O4@Ag NPs

Optical sensors based on chemically sensitive matrices/dyes have been used for accurate measurements of oxygen levels. In this study, the intensity-based response of highly sensitive tris(2,2′-bipyridyl) ruthenium(II) chloride [Ru(bpy)3]2+ dye to oxygen (O2) was analyzed in the polymeric ethylcellulose matrix (EC) in the presence of two magnetite forms; Fe3O4 and Fe3O4@Ag nanoparticles (NPs). Fe3O4 NPs were synthesized by flame spray pyrolysis (FSP) and then Fe3O4@Ag NPs were prepared by a core-shell coating method. Iron oxide polymorphs were characterized by using X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It was measured that the particles synthesized by the FSP technique have an average size of ˂60 nm Fe3O4, Fe3O4@Ag NPs, and 1-butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF4]) were used as additives for enhancement of the sensitivity of the [Ru(bpy)3]2+ dye to O2 gas. The effects of these additive materials were examined by photoluminescence spectroscopy (PL). [Ru(bpy)3]2+ dye doped nanofiber in the presence with the Fe3O4@Ag NPs additive yielded higher Stern-Volmer constant (KSV) and extended linear response range when compared with the sensing slides in the presence with Fe3O4 NPs and the additive-free forms. The higher response ratio (I0/I100) was found as 3.45 for the ruthenium dye doped EC nanofiber form in the presence with Fe3O4@Ag NPs. Also, KSV values were calculated as 2.41 × 10−2 between the concentration range of 0–100% [O2]. According to our knowledge, it is the first time Fe3O4 and Fe3O4@Ag NPs were used for the enhancement of oxygen sensitivity of the ruthenium dye.

An Effective Optical Dual Gas Sensor for Simultaneous Detection of Oxygen and Ammonia.

The development of a simple, low-cost sensor for the effective sensing of multiple gases in industrial or residential zones has been in high demand in recent days. In this article, we have proposed an optical sensor for the dual sensing of oxygen (O2) and ammonia (NH3) gases, which consists of oxygen and ammonia-sensitive fluorescent dyes coated individually on both sides of a glass substrate. An ethyl cellulose (EC) matrix doped with platinum (II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) serves as the oxygen-sensing material, whereas the NH3-sensing material includes an eosin Y fluorescent indicator immobilized within a cellulose acetate (CA) matrix. Both the oxygen and ammonia-sensitive materials were excited by the same LED light source with a 405 nm peak wavelength, while the corresponding emissions were detected separately for the selective sensing of the gases under study. The dual gas sensor exhibits maximum sensitivities of around 60 and 20 for oxygen and ammonia gases, respectively. The high sensitivity and selectivity of the proposed optical dual sensor suggests the feasibility of the simultaneous sensing of oxygen and ammonia for practical applications.