Macroemulsion Research Articles

Bioactive Lavandula angustifolia essential oil-loaded nanoemulsion dressing for burn wound healing. In vitro and in vivo studies.

The aim of this study was to develop a dressing with bioactive lavender in a new form of nanoemulsion, and to verify its biosafety and effectiveness in burn wound healing. As part of this research, the composition of the bioactive carrier of lavender oil in the form of a nanoemulsion obtained using ultrasound was optimised. The mean particle size of the internal phase and polydispersity were determined using the dynamic light scattering method using a Zestasizer NanoZS by Malvern and using cryo-transmission electron microscopy (TEM). These studies confirmed that the selected formulation had a particle size of approximately 180nm and remained stable over time. The preparation was also subjected to rheological analysis (viscosity approximately 480mPa·s) and a pH test (approximately 6). A macroemulsion (ME) with the same qualitative composition was developed as a reference. Nanoformulations and MEs were tested for skin penetration using Raman spectroscopy in an in vitro model. Research has shown that both formulations deliver oil to living layers of the skin. Subsequently, studies were conducted to confirm the effect of lavender oil in emulsion systems on the mitigation of the inflammatory reaction and its pro-regenerative effect on the wound healing process in an in vitro cell culture model. The safe concentration of the oil in the emulsion preparation was also determined based on preliminary in vivo tests of skin sensitisation and irritation as well as an hemocompatibility test of the preparation.

Physical features’ characterization of the water-in-mineral oil macro emulsion stabilized by a nonionic surfactant

Water-in-oil (w/o) emulsions are widely used in the food and pharmaceutical industries, among others. Moreover, the most common type of emulsion produced and handled in the oil industry processes is the w/o emulsion. This study investigates the features of a water-in-mineral oil macro-emulsion formulated with mineral oil as the continuous phase and Span 83 as the nonionic surfactant. Emulsions are prepared at room temperature according to the hydrophilic–lipophilic difference (HLD) theory and were tested for the mean droplet size and droplet size distribution, viscosity, and kinetic stability. An empirical correlation was introduced that estimates the viscosity of the water-in-mineral oil macro-emulsions and captures the non-Newtonian behavior at larger water fractions. The effect of electrolyte and internal phase concentration was specifically assessed on the emulsion flocculation and the stability of the system. Stability tests show a threshold electrolyte concentration exists after which droplets coalesce upon collision and flocculation. Salting out is most likely the responsible mechanism of phase separation in the emulsions with higher electrolyte concentrations. The results imply that sedimentation is accountable for the formation of different layers in emulsion with time. The sedimentation rate was intensified for emulsion with smaller water content (64% variation in 3 days between 10% emulsion and 40% emulsion) and concentrated emulsions were found to be more stable. Also, the size of the droplets was influenced by the NaCl concentration, surfactant concentration, and phase ratio.

The effect of Macro and Nano-emulsions of cinnamon essential oil on the properties of edible active films.

The effect of Nano‐emulsion (NE) and Macro‐emulsion (ME) of cinnamon essential oil (CEO) on the properties of carboxymethyl cellulose (CMC)‐based films was investigated. MEs (diameters of 242–362 nm) and NEs (diameters of 59–80 nm) of CEO were produced through Ultra‐Turrax and Ultrasonication, respectively. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) images showed different morphologies in the films containing ME and NE, also a denser and more uniform microstructure was observed in the NE films in comparison with the ME ones. The higher stability of NE in the CMC matrix, increased the thickness of the resulted films. The water vapor permeability (WVP) was increased from 2.59 × 10–9 g/ms Pa in the control film to 4.43 × 10–9 g/m s Pa in the ME film, and decreased to 1.80 × 10–9 g/ms Pa in the NE film. Adding CEO led to more flexible films with enhanced strain at break (SAB) from 53.56% in the control film to 80% and 94.77% in the ME and NE films, respectively. The antifungal indices against A. niger and M. racemous were 14.16% and 20.82% in the ME films, and were improved to 18.81% and 25% in the NE ones.

Response surface study and kinetic modelling of biodiesel synthesis catalyzed by zinc stearate

This contribution reports experimental and theoretical studies on the transesterification of soybean oil with methanol catalyzed by zinc stearate. This reaction produces fatty acid methyl esters (FAME) and glycerol, and di- and monoglycerides as intermediate products.Response Surface Methodology was used to study the relationship between process variables and triglyceride conversion, FAME yield and initial rate. An increase in the catalyst concentration and in the methanol/oil molar ratio increased triglyceride conversion and FAME yield and decreased the initial turnover frequency values. The latter was associated with the formation of an emulsion in the reaction medium.A kinetic study of the reaction was performed. Two models were proposed. Model 1 assumed a complete mixing of the dissolved catalyst with the reactants and a second-order mechanism for the forward and reverse reactions, where the reaction system could be described as pseudo-homogeneous and the catalyst was dissolved in the reaction medium. Model 2 supposed that the dissolved catalyst formed part of a macro emulsion, with mass transfer resistance in the boundary layer around the droplets. The kinetic constants were determined, and Model 2 showed a better fit to the experimental data. The model and the kinetic parameters allow to generate reaction operation strategies.

Tissue Distribution of Astaxanthin Formulation in Rats

Background: Nano size emulsion of Astaxanthin has been successfully developed. However, its bioavailability enhancement benefit in form of concentration absorbed and tissue distribution has not been studied yet. Objective: This study investigated the relationship between globule size and tissue distribution of different types of astaxanthin formulation namely macro, nano and oil solution. Method: Twenty male rats were divided into four groups and orally fed with the formulations for seven days. The first, second, and third group of rats were fed with nano emulsion, macro emulsion and oil solution, respectively. The final group was used as negative control. The lungs, spleen, kidney, heart and liver were isolated for distribution study. Results: It was found that the nano size emulsion of astaxanthin contained the highest distribution in all organs while the highest concentration of astaxanthin was found in the spleen for each type of formulation. Conclusion: it is concluded that nano sized emulsion improved distribution and enhance the bioavailability of astaxanthin.

Investigation of synergistic effect of nanoparticle and surfactant in macro emulsion based EOR application in oil reservoirs

The present paper deals with the characterization of oil in water (O/W) emulsion stabilized by the synergistic effect of surfactant and nanoparticle for their application in enhanced oil recovery (EOR). The emulsions have been formulated using n-decane and paraffin oil, silica nanoparticle and two different surfactants, viz., anionic sodium dodecyl sulfate (SDS) and cationic cetyl trimethyl ammonium bromide (CTAB). The nanoparticle shows a synergetic effect in presence of surfactants which prevents the coalescence of dispersed oil droplets and lowers the interfacial tension (IFT) at the oil-water interface. The stability of emulsions was evaluated by particle size distribution, creaming behaviour, zeta potential and phase behaviour. The viscosity of emulsions remains stable at wide range temperature indicating thermal stability. The viscoelastic study indicates that the emulsions behave as a gel-like structure with a higher value of storage modulus (G′) than loss modulus (G″). The addition of polymer leads to improvement in viscosity and stability of the emulsion, proving its usefulness in the reservoir for recovery of heavy oil.

An Overview of Food Emulsions: Description, Classification and Recent Potential Applications

Emulsions take place partially or completely in the structures of many natural and processed foods or some foods are already emulsified in certain stages of production. In general “emulsion” is described as a structure created through the dispersion of one of two immiscible liquids within the other one in form of little droplets. Many terms are available to describe different emulsion types and it is very important to define and clarify these terms like “macro emulsion”, “nanoemulsion” and “multiple emulsion”. Nanoemulsions become increasingly important in food industry as an innovative approach in carrying functional agents. Application potential of multiple emulsions (W/O/W) is also stated to be very high in food industry. The two main strategic purposes of utilization of multiple emulsions in food applications are to encapsulate various aromas, bioactive compounds or sensitive food compounds and to allow the production of the low-fat products. This review provides an overview to the general terms of emulsion types, the role of various emulsifying agents, and the application potential of emulsions in food industry.

Capillary-driven mobility control in macro emulsion flow in porous media

We show that the mobility of an emulsion with drops larger than the porous throats is a strong function of the local capillary number; it falls as the interfacial forces become stronger (low capillary number). Emulsion drops have little effect on the fluid mobility at high capillary number. This flow behavior can be used as a selective mobility control mechanism driven by capillary forces. The flow rate and emulsion characteristics can be selected in such a way that fluid mobility near the injecting source remains high, allowing the emulsion to reach the location where the mobility control is needed. To prove the benefit of capillary-driven mobility control, we study the displacement of mineral oil by water and emulsion at two capillary numbers by measuring the volume of displaced fluid. Higher efficiency displacement due to high mobility of the displacing fluid only occurs at low capillary number.

Textile Softeners on Cotton Dyed with Direct Dyes: Reflectance and Fastness Assessments

Abstract In this research, cotton fabrics scoured with nonionic detergent were dyed with four different direct dyes (Thiazole, Disazo, Trisazo and Polyazo). The dyed fabrics were then treated with anionic, cationic, nonionic, micro and macro emulsion silicone softeners. CIELAB color coordinates (L∗, a∗, b∗, C∗ and h) were measured with reflectance spectrophotometer. The lightness (L∗ value) for samples dyed with disazo and polyazo direct dyes (orange and red dyes) showed an increase after treatment with all the mentioned softeners, while it was decreased for thiazole and trisazo dyed fabrics treated with anionic, cationic, micro and macro emulsion silicone softeners. The wash and light fastness properties of samples were measured according to ISO 105-CO5 and Daylight ISO 105-BO1. The washing fastness properties of some direct dyed samples were decreased after treatment with softeners. In the case of light fastness properties, it was decreased for most of the samples.