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David Julian Mcclements - One of the best experts on this subject based on the ideXlab platform.
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antimicrobial activity of pit fabricated cinnamon oil nanoemulsions effect of surfactant concentration on morphology of foodborne pathogens
Food Control, 2019Co-Authors: Piyanan Chuesiang, Ubonrat Siripatrawan, Romanee Sanguandeekul, David Julian Mcclements, Lynne MclandsboroughAbstract:Abstract The impact of surfactant concentration (10 to 20 wt%) on the antimicrobial activity of cinnamon oil nanoemulsions formed by the phase Inversion Temperature (PIT) method was studied against a number of foodborne pathogens: Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and Vibrio parahaemolyticus. Minimum inhibitory concentration (MIC), dynamic time kill, and changes in bacteria morphology were determined. Increasing non-ionic surfactant (Tween®80) concentration from 10 to 20 wt% increased the MIC values of the nanoemulsions. However, dynamic time kill plots revealed that nanoemulsions with higher surfactant concentrations (15 and 20 wt%) led to faster or more prolonged inhibition of bacteria compared to those with lower concentration (10 wt%) or with bulk cinnamon oil. Morphological changes of the bacteria were more promoted for nanoemulsions containing higher surfactant concentrations as shown by field emission scanning electron microscopy (FE-SEM). The antimicrobial activity of the cinnamon oil nanoemulsions was attributed to their ability to disrupt bacterial cell wall structures and promote expulsion of internal cellular material.
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Antimicrobial activity and chemical stability of cinnamon oil in oil-in-water nanoemulsions fabricated using the phase Inversion Temperature method
LWT, 2019Co-Authors: Piyanan Chuesiang, Ubonrat Siripatrawan, Romanee Sanguandeekul, David Julian Mcclements, Jason Szuhao Yang, Lynne MclandsboroughAbstract:Abstract The water-dispersibility and antimicrobial activity of cinnamon oil is enhanced by encapsulating it within oil-in-water nanoemulsions. This study investigated the impact of oil phase composition on the minimum inhibitory concentration (MIC) of cinnamon oil nanoemulsions against Escherichia coli, Salmonella enterica serovar Typhimurium (S. Typhimurium), Staphylococcus aureus and Vibrio parahaemolyticus. The nanoemulsions were fabricated using the phase Inversion Temperature (PIT) method, which simply involves heating a mixture of surfactant, oil, and water about the PIT and then quench cooling with stirring. The antimicrobial activity of cinnamon oil is largely due to cinnamaldehyde, which is highly susceptible to chemical degradation. For this reason, the decrease in cinnamaldehyde content and increase in a major reaction product (benzaldehyde) were measured in the cinnamon oil nanoemulsions during storage. The antimicrobial activity of cinnamon oil nanoemulsions increased (lower MICs) as the droplet size decreased. Cinnamaldehyde was degraded during emulsification and after storage for 31 days. These results have important implications for the improvement of the antimicrobial activity and stability of encapsulated cinnamon oil using nanoemulsion-based delivery systems.
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Optimization of cinnamon oil nanoemulsions using phase Inversion Temperature method: Impact of oil phase composition and surfactant concentration
Journal of Colloid and Interface Science, 2017Co-Authors: Piyanan Chuesiang, Lynne Mclandsborough, Ubonrat Siripatrawan, Romanee Sanguandeekul, David Julian McclementsAbstract:Abstract Essential oils, such as those isolated from cinnamon, are effective natural antimicrobial agents, but their utilization is limited by their low water-solubility. In this study, phase Inversion Temperature (PIT) was used to prepare cinnamon oil nanoemulsions. To this aim, it was hypothesized that cinnamon oil nanoemulsions could be fabricated by optimizing the oil phase composition and surfactant concentration of the system and their stability could be enhanced using a cooling-dilution method during the PIT. A mixture of cinnamon oil, non-ionic surfactant, and water was heated above the PIT of the system, and then rapidly cooled with continuous stirring, which led to the spontaneous generation of small oil droplets. The impact of oil phase composition and surfactant concentration on the formation and stability of the nanoemulsions was determined. Cinnamon oil nanoemulsions with the smallest mean droplet diameter (101 nm) were formed using 40:60 wt% of cinnamon oil and medium chain triglyceride (MCT) in the total lipid phase. Increasing surfactant concentration significantly decreased the mean droplet diameter of the nanoemulsions but did not alter their particle morphology. In addition, using the cooling-dilution method, the nanoemulsions were stable for at least 31 days when stored at 4 °C or 25 °C.
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formation and stability of solid lipid nanoparticles fabricated using phase Inversion Temperature method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016Co-Authors: Songran Gao, David Julian McclementsAbstract:Abstract Solid lipid nanoparticles (SLNs) are being investigated for their ability to encapsulate and protect lipophilic bioactive compounds in foods, supplements, and pharmaceuticals. In this study, the phase Inversion Temperature (PIT) method was used to fabricate SLNs using a model surfactant (Brij 30, C12E4)/oil (octadecane)/water system. Surfactant/oil/water (SOW) mixtures were maintained at a Temperature above the PIT, and then rapidly cooled to a Temperature below the lipid nanoparticle crystallization point. The PIT (≈40 °C) was determined by monitoring the turbidity versus Temperature profile of the SOW system during heating. The lipid nanoparticle crystallization point, melting point, and physical state were determined using differential scanning calorimetry (DSC). The stability of the lipid nanoparticles after fabrication depended on the storage Temperature relative to the PIT and melting/crystallization points. At Temperatures appreciably below their melting point (≈26 °C), the lipid nanoparticles were completely solid and stable to aggregation. At Temperatures around their melting point, the lipid nanoparticles were partially crystalline, which led to partial coalescence and gelation. At Temperatures appreciably above their melting point but below their PIT, the lipid nanoparticles were completely liquid and prone to coalescence and phase separation. These results have important implications for optimizing the fabrication and storage conditions required to produce stable nanoemulsions suitable for utilization in commercial products using low-energy methods.
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optimization of isothermal low energy nanoemulsion formation hydrocarbon oil non ionic surfactant and water systems
Journal of Colloid and Interface Science, 2014Co-Authors: Jennifer Komaiko, David Julian McclementsAbstract:Nanoemulsions can be fabricated using either high-energy or low-energy methods, with the latter being advantageous because of ease of implementation, lower equipment and operation costs, and higher energy efficiency. In this study, isothermal low-energy methods were used to spontaneously produce nanoemulsions using a model system consisting of oil (hexadecane), non-ionic surfactant (Brij 30) and water. Rate and order of addition of surfactant, oil and water into the final mixture were investigated to identify optimal conditions for producing small droplets. The emulsion phase Inversion (EPI) and spontaneous emulsion (SE) methods were found to be the most successful, which both require the surfactant to be mixed with the oil phase prior to production. Order of addition and surfactant-to-oil ratio (SOR) influenced the particle size distribution, while addition rate and stirring speed had a minimal effect. Emulsion stability was strongly influenced by storage Temperature, with droplet size increasing rapidly at higher Temperatures, which was attributed to coalescence near the phase Inversion Temperature. Nanoemulsions with a mean particle diameter of approximately 60 nm could be produced using both EPI and SE methods at a final composition of 5% hexadecane and 1.9% Brij 30, and were relatively stable to droplet growth at Temperatures <25 °C.
Yi-hong Xiu - One of the best experts on this subject based on the ideXlab platform.
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throttling process of the kerr newman anti de sitter black holes in the extended phase space
Physical Review D, 2018Co-Authors: Ze-wei Zhao, Yi-hong XiuAbstract:The throttling process of the Kerr--Newman--anti-de Sitter (KN--AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an adiabatic and isenthalpic (i.e., constant-mass) process for the KN--AdS black holes. The Joule--Thomson coefficient, Inversion Temperature, Inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum Inversion Temperatures, but only minimum ones that are around one half of the critical Temperatures of the KN--AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN--AdS black holes.
Ze-wei Zhao - One of the best experts on this subject based on the ideXlab platform.
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throttling process of the kerr newman anti de sitter black holes in the extended phase space
Physical Review D, 2018Co-Authors: Ze-wei Zhao, Yi-hong XiuAbstract:The throttling process of the Kerr--Newman--anti-de Sitter (KN--AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an adiabatic and isenthalpic (i.e., constant-mass) process for the KN--AdS black holes. The Joule--Thomson coefficient, Inversion Temperature, Inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum Inversion Temperatures, but only minimum ones that are around one half of the critical Temperatures of the KN--AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN--AdS black holes.
Conxita Solans - One of the best experts on this subject based on the ideXlab platform.
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phase behavior and nano emulsion formation by the phase Inversion Temperature method
Langmuir, 2004Co-Authors: Paqui Izquierdo, Jordi Esquena, Th F Tadros, N Azemar, Joseph C Dederen, Jin Feng, Maria Jose Garciacelma, Conxita SolansAbstract:Formation of oil-in-water nano-emulsions has been studied in the water/C12E4/isohexadecane system by the phase Inversion Temperature emulsification method. Emulsification started at the corresponding hydrophilic-lipophilic balance Temperature, and then the samples were quickly cooled to 25 degrees C. The influence of phase behavior on nano-emulsion droplet size and stability has been studied. Droplet size was determined by dynamic light scattering, and nano-emulsion stability was assessed, measuring the variation of droplet size as a function of time. The results obtained showed that the smallest droplet sizes were produced in samples where the emulsification started in a bicontinuous microemulsion (D) phase region or in a two-phase region consisting of a microemulsion (D) and a liquid crystalline phase (L(alpha)). Although the breakdown process of nano-emulsions could be attributed to the oil transference from the smaller to the bigger droplets, the increase in instability found with the increase in surfactant concentration may be related to the higher surfactant excess, favoring the oil micellar transport between the emulsion droplets.
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phase behavior and nano emulsion formation by the phase Inversion Temperature method
Langmuir, 2004Co-Authors: Paqui Izquierdo, Jordi Esquena, Th F Tadros, N Azemar, Joseph C Dederen, Jin Feng, Maria Jose Garciacelma, Conxita SolansAbstract:Formation of oil-in-water nano-emulsions has been studied in the water/C12Ē4/isohexadecane system by the phase Inversion Temperature emulsification method. Emulsification started at the corresponding hydrophilic−lipophilic balance Temperature, and then the samples were quickly cooled to 25 °C. The influence of phase behavior on nano-emulsion droplet size and stability has been studied. Droplet size was determined by dynamic light scattering, and nano-emulsion stability was assessed, measuring the variation of droplet size as a function of time. The results obtained showed that the smallest droplet sizes were produced in samples where the emulsification started in a bicontinuous microemulsion (D) phase region or in a two-phase region consisting of a microemulsion (D) and a liquid crystalline phase (Lα). Although the breakdown process of nano-emulsions could be attributed to the oil transference from the smaller to the bigger droplets, the increase in instability found with the increase in surfactant conce...
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formation and stability of nano emulsions prepared using the phase Inversion Temperature method
Langmuir, 2002Co-Authors: Paqui Izquierdo, Jordi Esquena, Th F Tadros, C Dederen, Maria Jose Garcia, N Azemar, Conxita SolansAbstract:Formation of O/W nano-emulsions has been studied in water/C12Ē4/oil systems by the phase Inversion Temperature emulsification method. Emulsification was carried out at the corresponding HLB (hydrophilic−lipophilic balance) Temperature, and then the emulsions were cooled fast to 25 °C. The influence of surfactant concentration and oil solubility on HLB Temperature, nano-emulsion droplet size, and stability has also been studied. Droplet size was determined by dynamic light scattering, and nano-emulsion stability was assessed, measuring the variation of droplet size as a function of time. The results obtained showed that the breakdown process of nano-emulsions studied could be attributed to Ostwald ripening. An increase of nano-emulsion instability with the increase in surfactant concentration and oil solubility was also found.
Giovanni Puglisi - One of the best experts on this subject based on the ideXlab platform.
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idebenone loaded solid lipid nanoparticles for drug delivery to the skin in vitro evaluation
International Journal of Pharmaceutics, 2012Co-Authors: Lucia Montenegro, Claudia Carbone, Chiara Sinico, Ines Castangia, Giovanni PuglisiAbstract:Abstract Idebenone (IDE), a synthetic derivative of ubiquinone, shows a potent antioxidant activity that could be beneficial in the treatment of skin oxidative damages. In this work, the feasibility of targeting IDE into the upper layers of the skin by topical application of IDE-loaded solid lipid nanoparticles (SLN) was evaluated. SLN loading different amounts of IDE were prepared by the phase Inversion Temperature method using cetyl palmitate as solid lipid and three different non-ionic surfactants: ceteth-20, isoceteth-20 and oleth-20. All IDE loaded SLN showed a mean particle size in the range of 30–49 nm and a single peak in size distribution. In vitro permeation/penetration experiments were performed on pig skin using Franz-type diffusion cells. IDE penetration into the different skin layers depended on the type of SLN used while no IDE permeation occurred from all the SLN under investigation. The highest IDE content was found in the epidermis when SLN contained ceteth-20 or isoceteth-20 as surfactant while IDE distribution into the upper skin layers depended on the amount of IDE loaded when oleth-20 was used as surfactant. These results suggest that the SLN tested could be an interesting carrier for IDE targeting to the upper skin layers.
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in vitro evaluation of idebenone loaded solid lipid nanoparticles for drug delivery to the brain
Drug Development and Industrial Pharmacy, 2011Co-Authors: Lucia Montenegro, Agata Campisi, Maria Grazia Sarpietro, Claudia Carbone, Rosaria Acquaviva, G Raciti, Giovanni PuglisiAbstract:Context: Solid lipid nanoparticles (SLN) are regarded as interesting drug delivery systems and their preparation techniques have gained a great deal of attention.Objective: To evaluate the feasibility of preparing idebenone (IDE) loaded SLN from O/W microemulsions by the phase-Inversion Temperature (PIT) method. Since SLN have been proposed to improve drug delivery to the brain, IDE was chosen as model drug due to its activity in the treatment of neurodegenerative diseases.Materials and Methods: Cetyl palmitate was used as solid lipid to prepare SLN containing two surfactant/cosurfactant mixtures, isoceteth-20/glyceryl oleate (SLN A) and ceteth-20/glyceryl oleate (SLN B) by the PIT method.Results and discussion: All the formulations tested showed a mean particle diameter ranging from 30 to 95 nm and a single peak in size distribution. Stability tests showed that SLN B were more stable than SLN A. IDE release was dependent both on the type of primary surfactant used and the amount of loaded drug. IDE-loade...
