Nanoemulsions as Ophthalmic Drug Delivery Systems Dhahir, Rasha Khalid; Al-Nima, Amina Mudhafar; Al-Bazzaz, Fadia Yassir
Turkish journal of pharmaceutical sciences,
10/2021, Letnik:
18, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Nanoemulsions are liquid-in-liquid dispersion with a droplet size of about 100 nm. They have a transparent appearance, high rate of bioavailability, and increased shelf life. Nanoemulsions mainly ...consist of oil, water, surfactant, and cosurfactant and can be prepared by high- and low-energy methods. Diluted nanoemulsions are utilized for the delivery of ophthalmic drugs due to their capability to penetrate the deep layers of the ocular structure, provide a sustained release effect, and reduce the frequency of administration and side effects. These nanoemulsions are subjected to certain tests, such as safety, stability, pH profile, rheological studies, and so on. Cationic nanoemulsions are prepared for topical ophthalmic delivery of active ingredients from cationic agents to increase the drug residence time on the ocular surface, reducing their clearance from the ocular surface and improving drug bioavailability. This review article summarizes the main characteristics of nanoemulsions, ophthalmic nanoemulsions, and cationic nanoemulsions and their components, methods of preparation, and the evaluation parameters for ophthalmic nanoemulsions.
Nanoemulsions are colloidal particulate systems with submicron size particles that function as medication carriers. Their diameter ranges from 10 to 1,000 nanometers. These carriers are solid spheres ...with an amorphous, lipophilic, negative-charged surface. To improve site-specificity, magnetic nanoparticles can be utilized. As a medication delivery method, they improve the medicine's therapeutic efficacy while reducing side effects and hazardous responses. Infections of the reticuloendothelial system (RES), enzyme replacement therapy in the liver, cancer treatment, and immunization are all examples of major applications. An emulsion is a biphasic framework in which one stage is circulated in the other stage as moment drops with widths changing from 0.1 to 100 lm. A thermodynamically unsound framework must be balanced out by adding an emulsifying specialist (emulgent or emulsifier). The scattered stage is otherwise called the interior stage or the irregular stage, though the scattering medium, outside stage, or persistent stage is the external stage. Middle of the road or interphase is one more name for the emulsifying specialist. A miniemulsion is a fine oil/water or water/oil dispersion stabilized by an interfacial coating of surfactant molecules with droplet sizes ranging from 20 to 600 nanometers. Nanoemulsions are transparent due to their tiny size.
Emulsion technology has been used for decades in the food industry to create a diverse range of products, including homogenized milk, creams, dips, dressings, sauces, desserts, and toppings. ...Recently, however, there have been important advances in emulsion science that are leading to new approaches to improving food quality and functionality. This article provides an overview of a number of these advanced emulsion technologies, including Pickering emulsions, high internal phase emulsions (HIPEs), nanoemulsions, and multiple emulsions. Pickering emulsions are stabilized by particle-based emulsifiers, which may be synthetic or natural, rather than conventional molecular emulsifiers. HIPEs are emulsions where the concentration of the disperse phase exceeds the close packing limit (usually >74%), which leads to novel textural properties and high resistance to gravitational separation. Nanoemulsions contain very small droplets (typically d < 200 nm), which leads to useful functional attributes, such as high optical clarity, resistance to gravitational separation and aggregation, rapid digestion, and high bioavailability. Multiple emulsions contain droplets that have smaller immiscible droplets inside them, which can be used for reduced-calorie, encapsulation, and delivery purposes. This new generation of advanced emulsions may lead to food and beverage products with improved quality, health, and sustainability.
The production of safe foods with little or no artificial preservatives is one of the foremost leading challenges for food manufacturing industries because synthetic antimicrobial agents and chemical ...food additives can cause severe negative effects on human health. However, there is an ever-increasing interest by consumers towards natural sources that have been aroused recently, and this increased consumer demand for safe food products has forced the food industries to use natural herbal and plant origins preservatives instead of synthetic preservatives for the production of safe foods. Traditionally, essential oils (EOs) obtained from numerous plant sources have been extensively encouraged for their putative health-promoting biological activities. The EOs are composed of complex mixtures encompassing copious individual compounds, which have been extracted by many methods. These diverse compounds display significant biological activities such as antioxidant and antimicrobial through different mechanisms. Nevertheless, their poor solubility in water, oxidation susceptibility, and volatility limit their use. To overcome these constraints, encapsulation is one of the best approaches to preserve the biological activities of EOs and minimize their effects on food sensory qualities. Herein, we have comprehensively enlightened the micro/nanoemulsion loaded with EOs to improve the physical—chemical and microbiological stability of various EOs, and further application of these EOs loaded systems in the food systems. This review confers the importance of EOs in terms of their main components, chemical and biological properties, including mode of action, effectiveness, synergistic effects as antimicrobials, and potential applications in the food system as a preservative.
Natural aldehydes, such as cinnamaldehyde, can be used to modify the properties of chitosan-based materials by covalent cross-linking the chitosan molecules. Due to the non-polarity and ...hydrophobicity of cinnamaldehyde, emulsification technique was used to prepare homogeneous cinnamaldehyde-chitosan films. Under optimized conditions, cinnamaldehyde nanoemulsions led to the successful fabrication of uniform and smooth chitosan films. FTIR analysis of the films indicated the formation of chitosan-cinnamaldehyde Schiff base. The cross-linked films strongly absorbed UV–visible light and inhibited the emission of fluorescent light, and may therefore provide good photo-protection. The thickness (26–61 μm) and transparency (clear to turbid) of the chitosan films were modulated by varying the aldehyde/amino group ratio. The mechanical properties and water vapor permeability of the films also depended on the amount of cinnamaldehyde nanoemulsion utilized. Chitosan films showed good antimicrobial activity, but had better antifungal than antibacterial activity.
The content of cinnamaldehyde-loaded nanoemulsion modulated the surface and cross-section structure of crosslinked chitosan films. Display omitted
•Active chitosan films were prepared by cross-linking with cinnamaldehyde nanoemulsions.•Cross-linked chitosan films showed good UV barrier properties.•The surface morphology of chitosan films showed granular structure.
Nanoemulsions have small droplet size and are kinetically stable colloidal systems. They have enhanced functional properties in comparison to conventional emulsions. The composition and structure of ...the nanoemulsions can be controlled for the encapsulation and effective delivery of bioactive lipophilic compounds. Nanoemulsions have potential application in the food industry for the delivery of nutraceuticals, coloring and flavoring agents, and antimicrobials. The nanoemulsion formulations of active ingredients can be used for developing biodegradable coating and packaging films to enhance the quality, functional properties, nutritional value, and shelf life of foods. This review focuses on preparation of food grade nanoemulsions using high-energy methods and low-energy approaches and their characterization for physical properties, stability, and microstructure. The application of nanoemulsion formulations for sustainable food processing and improving the delivery of functional compounds, such as colorants, flavoring agents, nutraceuticals, and preservatives or antimicrobial agents in foods has been discussed.
Rheology is a powerful and versatile analytical tool for providing information about changes in the composition, structure, and interactions of food emulsions. Moreover, an understanding of emulsion ...rheology is essential for designing efficient food processing operations and emulsion‐based foods with the desired physicochemical, sensory, and nutritional attributes, such as appearance, texture, flavor, shelf life, and bioavailability. This article provides a brief overview of the current understanding of food emulsions, with a focus on how their viscosity is related to the properties of the emulsion droplets present.
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•Curcumin, the major bioactive material turmeric, has wide range of biological features.•Curcumin exhibits a poor water solubility and low chemical stability.•Nanoemulsions delivery ...systems have been used to improve functional properties of curcumin.•The generation of nanoemulsions can be achieved through different preparation technologies.
Curcumin is widely acknowledged for its beneficial activities. However, its application has remained challenging due to its low aqueous solubility, biochemical/structural degradation and poor bioavailability. For these reasons, many researches are aimed at overcoming these limitations using lipid-based nanosystems to encapsulate curcumin, especially nanoemulsions. This review highlights the theoretical aspects and recent advances of preparation technologies (phase inversion temperature, phase inversion composition, ultrasonication, high pressure homogenization and microfluidization) for encapsulation of curcumin in nanoemulsions. Additionally, the specific factors in designing nanoemulsions systems that affect the chemical stability and in vitro bioaccessibility of the encapsulated curcumin are discussed. Also, the importance of nanoemulsions in improving antioxidant, anti-inflammatory and anticancer activities of curcumin is underlined. Curcumin-loaded nanoemulsions preparation technologies have been proposed to provide efficient, systematic, and practical protocols for improved applications of curcumin. Additionally, key factors that influence curcumin delivery include the nature of emulsifier, the type and the amount of carrier oil and emulsifier-curcumin interactions. The pharmacological activities of curcumin including antioxidant, anti-inflammatory and anticancer activities can be improved by nanoemulsions.
Curcumin is a natural antioxidant dye that has a wide spectrum of biological activities (e.g., anti-cancer, anti-hypertensive, anti-inflammatory and neuroprotective activities), and there is a high ...interest within the food industry to increase its use as a natural additive. However, due to its high hydrophobicity, it is difficult to incorporate into aqueous formulations and its bioavailability can be severely decreased. Lipid-based encapsulation systems such as nanoemulsions can help to overcome both of these drawbacks. In this study, curcumin-loaded nanoemulsions were produced by the emulsification inversion point method, for which some of the operational parameters were optimized. The most stable formulations were composed of 20% soybean oil, 10% Tween 80 and 20% glycerol and were produced with an anchor blade impeller operating at 300 rpm; this combination of parameters resulted in 0.07% encapsulation of the curcumin. After 60 days, 70% of the initial amount of curcumin remained in the nanoemulsions, which is a promising result when compared with those of other lipid-based encapsulation systems. The data also indicated that the catastrophic phase inversion occurred due to the formation of multiple o/w/o emulsions.
•Nanoemulsions with average diameter of 200 nm were produced by emulsion inversion point method.•Scalable process conditions (mechanical stirring and aqueous flow pumping) were optimized.•Glycerol as cosolvent was necessary for the production of nanoemulsions by the EIP method.•Nanoemulsions protected curcumin for a period longer than usually found in the literature.
Nanoemulsions are utilized within the food, pharmaceutical, and personal care industries because of their unique physicochemical properties and functional attributes: high optical clarity; prolonged ...stability; and, enhanced bioavailability. For many applications, it is desirable to utilize natural ingredients to formulate nanoemulsions so as to create “label-friendly” products. In this study, we compared the effectiveness of a number of natural emulsifiers at fabricating corn oil-in-water nanoemulsions using dual-channel microfluidization. These emulsifiers were either amphiphilic biopolymers (whey protein and gum arabic) or biosurfactants (quillaja saponin and soy lecithin). Differences in the surface activities of these emulsifiers were characterized using interfacial tension measurements. The influence of emulsifier type, concentration, and homogenization pressure on the efficiency of nanoemulsion formation was examined. The long-term stability of the fabricated nanoemulsions was also monitored during storage at ambient temperature. For all of the natural emulsifiers, nanoemulsions could be produced by dual-channel microfluidization, with the mean particle diameter decreasing with increasing emulsifier concentration and homogenization pressure. Whey protein isolate and quillaja saponin were more effective at forming nanoemulsions containing fine droplets than gum arabic and soy lecithin, with a lower amount of emulsifier required and smaller droplets being produced. This effect was attributed to faster emulsifier adsorption and a greater reduction in interfacial tension leading to more efficient droplet disruption within the homogenizer for saponins and whey proteins. This study highlights the potential of dual-channel microfluidization for efficiently producing label-friendly nanoemulsions from natural emulsifiers.
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•Dual-channel microfluidization could be used to efficiently produce nanoemulsions.•Nanoemulsions (d < 200 nm) could be prepared from most natural emulsifiers.•Droplet size decreased with homogenization pressure and emulsifier level.•Whey protein and saponin were more effective than gum arabic and lecithin.
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