Viscosity Of Ethyl Cellulose Research Articles

Preparation of resveratrol-loaded ethyl cellulose microspheres via foam-transfer and its application performances

Resveratrol (Res) has been widely used in personal-care and pharmaceutical products due to its anti-oxidant, anti-inflammatory, cardioprotective and anti-cancer properties. However, the direct application of Res as functional additives have been limited due to its insolubility and instability. In this work, Res is loaded on the biodegradable ethyl cellulose (EC) carrier to prepare highly porous EC/Res microspheres via a foam-transfer method to understand the sustained release and the degradation property. The experimental results show that when the PVA concentration = 2.5 wt%, the stirring rate = 600 rpm, the oil/water (O/W) ratio = 1:2, the polymer concentration = 1:25, the heating rate = 0.33 °C/min, and the viscosity of EC = 90 ~ 110 mpa.s, the EC/Res microspheres are obtained with a yield up to 80.70 wt% and an encapsulation efficiency of 73.89% via the batch-process; the EC/Res microspheres are further produced continuously with a higher encapsulation efficiency of 90.63% with a yield of 85.58 wt%. The EC/Res microsphere reaches a cumulative release rate up to 91.97 wt% in the phosphate buffer solution (PBS) at pH = 5.0 under 45 °C for 120 h. After the EC/Res microspheres degraded in PBS (pH = 7.4) for 45 days, the hardness decreased from 12.01 ± 0.56 MPa to 4.02 ± 0.45 MPa. This work thus provides a practical solution for Res’s application as sustained release functional additives.

Physicochemical properties and intermolecular interactions of a novel diacylglycerol oil oleogel made with ethyl cellulose as affected by γ-oryzanol

With an aim to prepare a novel formula for healthy oleogel, diacylglycerol (DAG)-rich oil as a continuous oil phase, ethyl cellulose (EC) as a gelator and γ-oryzanol (GO) as an antioxidant were used. Effects of EC viscosity and EC/GO mass ratio on the physicochemical properties were studied. Besides, interactions between the components were analyzed by Fourier transform infrared spectroscopy and molecular dynamics (MD) simulation. The EC with a viscosity of 18–22 mPa s resulted in slightly higher oil binding capacity (99.84% vs 98.55% at 10% EC, and 99.92% vs 99.49% at 12% EC) and significantly stronger hardness and gel strength of DAG oil oleogels than EC with a viscosity of 45–55 mPa s. Moreover, the hardness and rheological properties of oleogels were negatively correlated to GO addition. MD simulation was used to understand this effect of GO addition, showing that EC-GO complex had lower binding energy (−107.14 kJ/mol) than the complexes of GO-DAG (−105.64 kJ/mol) and EC-DAG (−101.96 kJ/mol), leading to the disruption of the capacity of EC to structure DAG-rich oil. Interactions between the components were mainly governed by van der Waals interactions. The peroxide value of the oleogels decreased by 1.89 mmol/kg as EC18/GO mass ratio changed from 12:0 to 12:4, indicating good antioxidant activity of GO. Overall, the characteristics of DAG oil oleogels could be modulated by the addition of GO. The study may provide considerable potential to develop healthy and stable oleogels with high DAG, low saturated and trans-fatty acids for food industry.

Study on the antioxidative mechanism of tocopherol loaded ethyl cellulose particles in thermal-oxidized soybean oil

Our previous study proposed preparation method of tocopherol (Toc) loaded ethyl cellulose (EC) particles as antioxidant due to instability of Toc under high temperature. The present study aimed to explore the antioxidant mechanism of loaded particles. Results showed that loaded particles prepared by EC of different viscosities (EC9, EC70, EC200) had antioxidative effect, and the antioxidant activity increased with EC viscosity. Fourier transform infrared analysis demonstrated that the interaction between EC and tocopherol was mainly hydrogen bond. Loaded particles retained effectively the thermal degradation of Toc and thus enhanced the antioxidant activity. Further investigation into thermal oxidation of EC inferred the possible antioxidative mechanism included two aspects. One was that Toc was fixed in the network structure of loaded particles formed by EC to provide a barrier for avoiding degradation. Another was that EC and Toc acted on different stages of lipid oxidation, playing the antioxidative effect together.

Epoxy resin/ethyl cellulose microcapsules prepared by solvent evaporation for repairing microcracks: Particle properties and slow-release performance

Slow-release and self-healing microcapsules were prepared by solvent evaporation with epoxy resin(ER) and ethyl cellulose(EC) as core material and wall material respectively. Particle properties, permeability of core materials and slow-release performance of microcapsules were characterized by environmental scanning electron microscope, laser particle analyzer, high performance liquid chromatography and ultraviolet-visible spectrophotometer. The results showed that ER/EC microcapsules possessed a spherical shape and uniform distribution. The particle size of microcapsules was generally distributed between 75∼175 μm. Compared with ER/EC(N14 and N25) microcapsules, ER/EC(N7) microcapsules had distinguished holes which had a favorable permeability on the surface. ER/EC(N7) microcapsules had a better slow-release performance, with the cumulative release rate of core material reaching 66.1 % for 48 h. In contrast with ER/EC(N7) microcapsules, the encapsulation efficiency and loading content of ER/EC(N25) microcapsules were improved by 5.4 % and 5 %, respectively. The formation of holes on the surface of microcapsules was related to the evaporation of organic solvent (Dichloromethane) passing through the wall material. Therefore, the size of holes on the surface of microcapsules was smaller and the amount of that was larger with the increase of EC viscosity grade. The release behavior of ER/EC microcapsules can be explained by First-order kinetic model, Higuchi model and Korsmeyer-peppas model.

Fabrication and physicochemical and antibacterial properties of ethyl cellulose-structured cinnamon oil oleogel: relation between ethyl cellulose viscosity and oleogel performance.

Edible packaging and coating with natural antimicrobials such as essential oils is an emerging technology for the control of pathogen growth in meat products. This study aimed to explore ethyl cellulose (EC) of three viscosities for the structuring of cinnamon essential oil (CEO), and investigated the physicochemical properties of the resulting oleogel and its emulsion, as well as the corresponding antibacterial activity in model and actual environments (as in sausages). The network structure of CEO-EC oleogel was more compact with increased EC viscosity, thereby improving the binding capacity and stability of the oil. A positive correlation was found between EC viscosity and particle size of the CEO-EC emulsion. The 45 cP CEO-EC emulsion exhibited greatest antimicrobial activitiy in models with Escherichia coli (E. coli) O157:H7 (ATCC 700927) and Staphylococcus aureus (S. aureus) (ATCC 29213), as well as in sausage, with respect to total counts of mesophilic bacteria, psychrotrophs, lactobacilli, and pseudomonads. The CEO-EC oleogel has antibacterial activity, determined by the EC viscosity, that provide potential antibacterial protection for meat products and might be especially suitable for some traditional Chinese ready-to-eat sausages without strictly sealed packaging. © 2019 Society of Chemical Industry.

Peculiar effect of polyethylene glycol in comparison with triethyl citrate or diethyl phthalate on properties of ethyl cellulose microcapsules containing propranolol hydrochloride in process of emulsion-solvent evaporation

Plasticizers play a crucial role in various process of microencapsulation. In this study, the effect of incorporation of plasticizer in process of emulsion solvent evaporation was investigated on properties of ethyl cellulose (EC) microcapsules containing propranolol hydrochloride. The effect of plasticizer type and concentration were investigated on characteristics of microcapsules prepared from different viscosity grades of EC. Product yield, encapsulation efficiency, mean particle size, shape, surface characteristics, solid state of drug, and drug release profiles were evaluated. Product yield and encapsulation efficiency were not dependent on plasticizer type and concentration. However, encapsulation efficiency decreased with increase in EC viscosity grade in the most of the cases. The mean particle size was in the range of 724–797 μm and was not dependent on plasticizer type. Microcapsules formed in the presence of PEG had a very smooth surface with few pores. XRD and DSC studies revealed a reduction of drug crystallinity after microencapsulation especially in presence of PEG. The results showed that the presence of TEC and DEP with different concentrations had no marked effect on drug release from microcapsules containing different viscosity grades of EC. This was not the case when PEG was used, and despite its water solubility it reduced the drug release rate noticeably. The reduction in the drug release in the presence of PEG was concentration-dependent. The use of PEG as a plasticizer in process of emulsion solvent evaporation highly improved the EC microcapsule structure and retarded the drug release rate and therefore is recommended.

Investigation of a new pH-responsive nanoparticulate pore former for controlled release enteric coating with improved processability and stability

Water-soluble polymers are often used as pore formers to tailor permeability of film-forming hydrophobic polymers on coated dosage forms. However, their addition to a coating formulation could significantly increase the viscosity thus making the coating process difficult. Moreover, the dissolution of pore formers after oral administration could compromise film integrity resulting in undesirable, inconsistent release profiles. Therefore, a non-leaching, pH-responsive nanoparticulate pore former is proposed herein to preserve film integrity and maintain pH-dependent permeability. Poly(methacrylic acid)-polysorbate 80-grafted-starch terpolymer nanoparticles (TPNs) were incorporated within an ethylcellulose (EC) film (TPN-EC) by casting or spray coating. TPNs at 10%wt (pore former level) only increased viscosity of EC coating suspension slightly while conventional pore formers increased the viscosity by 490–11,700%. Negligible leaching of TPNs led to superior mechanical properties of TPN-EC films compared to Eudragit® L-EC films. As pH increased from 1.2 to 6.8, TPN-EC films with 10% pore former level exhibited an 8-fold higher diltiazem permeability compared to Eudragit® L-EC films. The pH-dependent drug release kinetics of diltiazem HCl beads coated with TPN-EC films was tunable by adjusting the pore former level. These results suggest that the TPNs are promising pH-sensitive nanoparticulate pore formers in EC-coated dosage forms.

Effect of Variation in Viscosity Grade of Ethycellulose on Theophylline Microcapsule Properties Prepared by Emulsion Solvent Evaporation.

There are conflicting reports regarding the effect of polymer viscosity grade on microcapsule properties. The aim of the present study was to investigate the effect of just viscosity grade of ethylcellulose (EC) (not polymeric solution) on properties of theophylline microcapsules prepared by emulsion solvent evaporation. The effect of EC viscosity grade and drug:polymer ratio was investigated on microcapsule properties (yield, particle size, morphology, surface characteristics and drug release). Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) were implemented to study the interaction and solid state of drug. The microcapsules were compressed in the presence of excipients and drug release was evaluated. The yield of microencapsulation and encapsulation efficiency at 1:1 drug:polymer ratio was dependent on EC viscosity. Microcapsules were spherical with some pores on their surfaces. The number of pores was more and their size was bigger for EC 100 cP microcapsules. Theophylline remained in crystalline form after encapsulation. DSC studies confirmed lack of interaction between drug and polymer. The drug release was rapid at 2:1 drug:polymer whilst it was slowed down at 1:1 drug:polymer ratio. Microcapsules obtained from EC 100 cP showed slightly faster drug release at latter ratio. Marginal changes in release rate were observed after compression of microcapsules. All viscosity grades of EC were able to sustain the release of the drug from microcapsules. Considering the similar release profiles for microcapsules prepared from different viscosities of EC, the use of lower viscosity grade of EC is recommended due to the ease of production and also less processing time.

Ethylcellulose solvent substitution method of preparing heat resistant chocolate

In the present study a structuring technique was developed to produce chocolate which resists deformation at temperatures above 40°C. It was hypothesized that by adding ethylcellulose (EC) solubilized in ethanol (EtOH) to chocolate and evaporating the EtOH an organogel could be formed in situ with the fat phase of the chocolate. Heat resistant chocolate (HRC) was produced by mixing a 20% EC in EtOH solution with molten chocolate. The EtOH was evaporated and the resulting chocolate was incubated at 40°C for 2h and tested for hardness. The effect of various EC viscosities (4, 10, 20, 22, and 45cP) and concentrations ranging from 1.0 to 2.2% on different types of chocolates was studied. Milk chocolate containing 1.9% EC had a hardness of 26.0N whereas the control chocolate was too soft to be tested. Further experiments revealed that white and dark chocolates had hardnesses of 29.5 and 10.5N, respectively. The hardness of the chocolate was dependent on the chocolate formulation and concentration of EC, and independent of EC viscosity. It was observed that the addition and evaporation of EtOH from the compound milk chocolate samples led to an increase in the lightness of the chocolate surface if the EtOH was evaporated at temperatures of 40°C or higher. Addition of EC to chocolate represents a new strategy for the manufacture of HRC. Future work should focus on determining the mechanism by which heat resistance is achieved in these chocolates.

Fractionation of ethylcellulose oleogels during setting

The use of ethylcellulose (EC) polymers as a means to structure edible oils for fat replacement is beginning to show great promise and the use of these 'oleogels' has recently been shown to be feasible in food products. These gels are very versatile, as the mechanical properties can be tailored by altering either the fatty acid profile of the oil component, or the viscosity or concentration of the polymer component. Here we report the observation that certain formulation of EC oleogels tend to separate into two distinct phases; a soft interior core surrounded by a firm exterior sheath. It was found that the extent of this effect depends on EC viscosity, and can also be induced through the addition of certain surfactants, such as sorbitan monostearate and sorbitan monooleate, though not by glycerol monooleate. Although the two visually distinct regions were shown to be chemically indistinct, the cooling rate during gel setting was found to play a large role; rapid setting of the gels reduces the fractionation effect, while slow cooling produced a completely homogeneous structure. In addition, by reheating only the soft region of the gel, a firm and soft fractionated gel could again be produced. Finally, it was observed that oleogels prepared with castor oil or mineral oil have the ability to remove or induce the gel separation, respectively. Taken together, these results indicate chemical interactions may incite the separation into two distinct phases, but the process also seems to be driven by the cooling conditions during gel setting. These findings lend insight into the EC-oleogel gelation process and should provide a stepping stone for future research into the manufacturing of these products.

Formulation and Evaluation of Press Coated Tablets for Pulsatile Drug Delivery Using Hydrophilic and Hydrophobic Polymers

The aim of present investigation was to develop press coated tablet for pulsatile drug delivery of ketoprofen using hydrophilic and hydrophobic polymers. The drug delivery system was designed to deliver the drug at such a time when it could be most needful to patient of rheumatoid arthritis. The press coated tablets containing ketoprofen in the inner core was formulated with an outer shell by different weight ratio of hydrophobic polymer (micronized ethyl cellulose powder) and hydrophilic polymers (glycinemax husk or sodium alginate). The release profile of press coated tablet exhibited a lag time followed by burst release, in which outer shell ruptured into two halves. Authors also investigated factors influencing on lag time such as particle size and viscosity of ethyl cellulose, outer coating weight and paddle rpm. The surface morphology of the tablet was examined by a scanning electron microscopy. Differential scanning calorimeter and Fourier transformed infrared spectroscopy study showed compatibility between ketoprofen and coating material.

In vitro and in vivo evaluation of ranitidine hydrochloride loaded hollow microspheres in rabbits

The objective of this investigation was to develop the hollow microspheres as a new dosage form of floating drug delivery systems with prolonged stomach retention time. Hollow microspheres containing ranitidine hydrochloride (RH) were prepared by a novel solvent diffusion-evaporation method using ethyl cellulose (EC) dissolved in a mixture of ethanol and ether (6:1.0, v/v). The yield and drug loading amount of hollow microspheres were 83.21+/-0.28% and 20.71+/-0.32%, respectively. The in vitro release profiles showed that the drug release rate decreased with increasing viscosity of EC and the diameter of hollow microspheres, while increased with the increase of RH/EC weight ratio. Hollow microspheres could prolong drug release time (approximately 24 h) and float over the simulate gastric fluid for more than 24 h. Pharmacokinetic analysis showed that the bioavailability from RH-hollow microspheres alone was about 3.0-times that of common RH gelatin capsules, and it was about 2.8-times that of the solid microspheres. These results demonstrated that RH hollow microspheres were capable of sustained delivery of the drug for longer period with increased bioavailability.

APPLICATION OF GELATIN FOR ENCAPSULATING ASPIRIN INTO ETHYL CELLULOSE MICROCAPSULE IN AN O/W EMULSION

The application of gelatin protective colloid for microencapsulating aspirin in ethylcellulose was demonstrated using an oil-in-water emulsification/solvent evaporation technique. The gelatin concentration, alcohol co-solvent amount, and ethylcellulose viscosity were investigated by analyzing the recovered weight, particle size distribution, drug loading efficiency, aspirin release rate, surface characteristics, and release kinetics. Results showed that recovery increased with greater concentrations of gelatin (up to 1%). Adding co-solvent (ethanol) also changed the microcapsule particle size distribution. Higher recovery and release rates were obtained when the ethanol content in polymer solvent was at 25% and the viscosity of ethylcellulose was low (45cps). The release rate followed Higuchi matrix release kinetics, suggesting a monolithic system with aspirin uniformly distributed over the microcapsule.

In vitro modified release of acyclovir from ethyl cellulose microspheres

The aim of this study was to demonstrate a sustained-release microparticulate dosage form for acyclovir via an in vitro study. Ethyl cellulose was selected as a model encapsulation material. All of the microspheres were prepared by an oil-in-water solvent evaporation technique. A 23 full factorial experiment was applied to study the effects of the viscosity of polymer, polymer/drug ratio, and polymer concentration on the drug encapsulation efficiency and the dissolution characteristics. The encapsulation efficiency of acyclovir in microspheres was in the range of 20.0-56.6%. Increase in the viscosity of ethyl cellulose and the ratio of CH2Cl2/ethyl cellulose increased drug encapsulation efficiency. The drug continuously released from microspheres for at least 12 h, and the release rate depended on the pH of the release medium. The sustained release characteristic was more prominent in the simulated intestine fluid than in the simulated gastric fluid. A faster release of drug was observed when a high viscosity polymer was used. The decomposition of acyclovir significantly decreased when encapsulated by ethyl cellulose, especially when stored at 37 and 50 °C.

Effect of Formulation Variables on Dissolution Profile of Diclofenac Sodium from Ethyl- and Hydroxypropylmethyl Cellulose Tablets

AbstractThe effects of formulation variables on the release profile of diclofenac sodium from ethyl cellulose (EC) and hydroxypropylmethyl cellulose (HPMC) matrix tablets were investigated. With increase in viscosity of ethyl cellulose used in nonaqueous granulation, a decrease in drug release from the tablets was observed, while the percentage of fines articles passed through 60 mesh) in the granulation had a significant effect on the dissolution profile. Granules containing 15% fines exhibited slow release of the drug in comparison to those containing 30% fines with EC matrices. An analysis of kinetics of drug release from hydrophobic EC matrix showed Fickian diffusion regulated dissolution. Drug release from HPMC tablets followed an apparent zero-order kinetics.

Controlled release captopril microcapsules: Effect of ethyl cellulose viscosity grade on thein vitrodissolution from microcapsules and tableted microcapsules

Captopril microcapsules were prepared using four different viscosity grades of ethyl cellulose (core: wall ratios 1:1, 1:2 and 1:3) by temperature induced coacervation from cyclohexane. In vitro dissolution studies in 0.1 M hydrochloric acid showed that the drug release was dependent on the core to wall ratio, the viscosity grade of the ethyl cellulose and thus the total viscosity of the coacervation system. Viscosity grade of greater than 100 c.p. was unsuitable for microencapsulation by coacervation method at the concentration used. The surface characteristics of a 1:2 core to wall ratio were studied by scanning electron microscopy. The surface of the microcapsules prepared with 10 c.p. viscosity grade was comparatively more porous with larger size pores than 50 c.p. viscosity grade of ethyl cellulose. However, 300 c.p. viscosity grade showed incomplete wall formation. The microcapsules did not fragment during dissolution, alter in shape or size, or show evidence of enlargement of the surface pores. The tensile strength of tablets prepared at constant pressure from each batch of microcapsules (mean diameter 675 microns) increased as both the core to wall ratios and the viscosity of ethyl cellulose increased. The dissolution rate of the drug from tableted microcapsules was significantly delayed. The in vitro release gave best correlation with first order release kinetics when compared to zero-order and square-root-of-time equations.

Preparation and evaluation of ethylcellulose microcapsules of indomethacin

Indomethacin was microencapsulated with ethylcellulose using a modified spherical agglomeration process, aiming at a sustained release preparation without side effects on the stomach. The surface morphology of the microcapsules was examined using scanning electron microscopy. The microcapsules were porous and spherical, and their porosity increased with increasing the viscosity of ethylcellulose.In vitro dissolution process followed Higuchi’s diffusion model for first 3 hr. Release rate of the drug from microcapsules decreased as the viscosity of ethylcellulose or the weight ratio of indomethacin to ethylcellulose was decreased. The release rate also decreased with increasing the microcapsule size. The microcapsules induced less gastric ulcer in rats than raw drug.