INTRODUCTION:

Medicinal molecules are delivered by a colloidal particle system called a nanoemulsion, which has particles in the submicron size range. Their sizes vary from 10 to 1,000 nm. These carriers are solid spheres with a negative-charged, amorphous, lipophilic surface. The site specificity can be increased by using magnetic nanoparticles.

They lessen hazardous and unfavorable effects while enhancing the medication's therapeutic efficacy as a drug delivery system. Among the main uses are immunization, liver enzyme replacement therapy, cancer treatment, and treatment for reticuloendothelial system (RES) infections. One phase is extensively dispersed in the other phase as microscopic droplets with sizes ranging from 0.1 to 100 lm in an emulsion, a biphasic system. Although the solution is thermodynamically unstable, the existence of It can be stabilized by an emulsifying agent, sometimes referred to as an emulgent or emulsifier. The dispersed phase is also known as the internal phase or the discontinuous phase, whereas the outer phase is also known as the dispersion medium, exterior phase, or continuous phase. Miniemulsions, also known as nanoemulsions, are fine water/oil or oil/water dispersions stabilized by an interfacial coating of surfactant molecules, with droplet sizes ranging from 20 to 600 nm. Because of their small size, nanoemulsions are transparent. Three distinct types of nanoemulsions are possible to produce: Water droplets are distributed throughout the continuous oil phase in (a) oil nanoemulsions containing water, (b) water nanoemulsions containing oil, and (c) water nanoemulsions (oil is distributed in the continuous aqueous phase).¹ Due to their small droplet size and distinct stability, nanoemulsions have become a very adaptable delivery technology that are being used in a wide range of sectors. These nanoscale dispersions, which usually have droplet sizes between 20 and 200 nanometers, have several advantages over traditional emulsions, including as increased stability, better bioavailability, and customized functionality. As a result, it is now crucial for researchers, formulators, and business experts to comprehend the creation, properties, and uses of nanoemulsions. In this thorough analysis, we explore the complex world of nanoemulsions, exploring the subtleties of their characterization, the complexities of their formulation, and the wide range of uses that take use of their special qualities. By combining new developments and existing knowledge in the field, our goal is to offer a thorough resource to practitioners and researchers who want to fully utilize nanoemulsions in a variety of industries.² A crucial part of the creation of nanoemulsions is their formulation, which affects their performance, stability, and suitability for use in a range of systems. We examine the many approaches used to create nanoemulsions, from traditional high-pressure homogenization to novel phase inversion methods. We also discuss how surfactants, co-surfactants, and other additives help stabilize nanoemulsions and modify their physicochemical characteristics to suit particular application needs.

Advantages of nanoemulsion:

1. Eliminates fluctuations in absorption

2. Boosts the rates of absorption.

3. Encourages the solubilization of lipophilic medications.

4. Provides water-insoluble pharmaceutical dose forms in aqueous form.

5. Promotes better bioavailability.

6. There are several methods of administering the medication, such as topical, oral, and intravenous.³

7. Using Nanoemulsion as a delivery system increases effectiveness allowing the overall dose to be decreased and minimising unwanted effects.⁴

Disadvantages of Nanoemulsion Based Systems:

1. The stabilisation of the Nanodroplets requires the use of a high concentration of cosurfactants and surfactants.

2. Limited ability to dissolve compounds with high melting points.

3. The surfactant used in pharmaceutical applications must not be harmful.

4. Environmental factors like temperature and pH have an impact on the stability of nanoemulsions. When patients receive nanoemulsion, these variables alter.⁴

Components of nanoemulsion:

The primary constituents of nanoemulsions consist of three elements: 1. Oil; 2. Surfactant/Co surfactant; 3. Aqueous phase. Various types of oils are available, such as castor, corn, coconut, evening primrose, linseed, mineral, olive, peanut, and so forth. A crude temporary emulsion resulting from an oil and water mixture will separate into two distinct phases upon standing due to the consolidation of dispersed globules; emulsifiers or emulsifying agents can provide stability to these systems. Nanoemulsions are predicated on low interfacial tension, as opposed to coarse emulsions micronized by external energy⁵. When cosurfactants are added, a thermodynamically stable nanoemulsion forms spontaneously; this is made possible. Since the droplet size in the dispersed phase is usually less than 140nm, liquids with nanoemulsions are transparent. There are several ways that medications are given to patients who use them.⁶ The use of characterization techniques is essential for clarifying the functional and structural characteristics of nanoemulsions, which in turn helps with formulation optimization and quality assurance. We explore a wide range of characterisation approaches in this review, such as advanced microscopy methods, zeta potential measurement, droplet size analysis, and rheological characterization. Nanoemulsions provide customized solutions to meet urgent issues and open up new possibilities in a variety of fields, including medicine delivery, food encapsulation, cosmetics formulation, and agricultural applications, opportunities. Through clarifying the range and complexity of nanoemulsion uses, we hope to stimulate further creativity and research in this quickly developing area. To sum up, this paper provides a thorough overview of nanoemulsions and provides information on their characterisation, synthesis, and uses in a range of industries. Our goal is to support informed decision-making and encourage additional developments in this fascinating area of research and development by identifying new trends and combining current knowledge.

Formulation Aspects and Method of Preparation of Nanoemulsion:

Complex colloidal systems known as nanoemulsions are made up of two immiscible phases, water and oil, which are stabilized by surfactants and occasionally co-surfactants. A number of essential elements and techniques are used in the formulation process to produce stable dispersions with specialized qualities appropriate for certain uses. Nanoemulsions have been made by a variety of techniques, such as phase inversion, solvent evaporation, high pressure homogenization, microfluidization, spontaneous emulsification, and hydrogel formation. Various techniques have been investigated to describe these nanoemulsions that are being used as drug delivery systems. The two primary techniques for creating nanoemulsions are the persuasive method and the brute force method.⁷

Components of Nanoemulsions:

Oil Phase:

The functioning and physicochemical characteristics of nanoemulsions are greatly influenced by the choice of oil phase⁸. Based on their solubility, stability, and suitability for the desired application, many types of oils, such as synthetic oils like medium-chain triglycerides, natural oils like olive and soybean oil, and essential oils like peppermint and tea tree oil, can be used.

Aqueous Phase:

In nanoemulsions, the aqueous phase functions as the continuous phase and affects the rheology, stability, and biocompatibility of the mixture. It could consist of electrolytes, water, or other substances mixed with aqueous solutions. The stability and performance of nanoemulsions can be greatly impacted by the makeup and pH of the aqueous phase, hence during formulation, attention must be taken to optimize these parameters.

Surfactants and Co-surfactants:

Surfactants and co-surfactants are essential for stabilizing nanoemulsions because they lessen the tension that exists between the water and oil phases' interfacial surfaces. Co-surfactants increase the effectiveness of surfactants and aid in the creation of small droplet sizes, whereas surfactants adsorb at the oil-water interface and provide a protective coating around the scattered droplets. Nonionic (like Tween or Span), ionic (like sodium dodecyl sulfate), and zwitterionic surfactants are examples of common surfactants.⁹

FORMULATION TECHNIQUES:

High-Pressure Homogenization:

For emulsification, a range of commercially available equipment is available. The three most crucial ones are high-pressure homogenizers, sonifiers, and rotor-statator systems. Nano-sized droplets are created in this method by passing surfactants and co-surfactants via a tight gap or valve while the oil and aqueous phases are under high pressure.¹⁰

Persuasion method/phase inversion technique:

The plausible method of generating nanoemulsions involves the generation of minuscule dispersions during phase transitions caused by changing one of the two variables (composition or temperature) while maintaining a constant value for the other. The addition of salt to (O/W) nanoemulsions containing an ionic emulsifier changes the electric charge of the surfactants, creating a (W/O) emulsion system. At a certain level, this process can take place, leading to the creation of a bicontinuous phase that finally encapsulates the phases of water and oil to create O/W nanoemulsions.⁷

Brute force method:

In order to get the oil droplets down to the nanoscale, this method uses brute force. Among the instruments employed in the creation of nanomeulsions are high frequency ultrasonic devices, small pore membranes, high pressure homogenizers, and high speed mixers. The properties of nanoemulsions, like their small size, optical transparency, and high kinetic stability, are dependent on processing variables like emulsification time, mixing intensity, energy input, and emulsifying path, in addition to the composition of the variables. Nanoemulsion can also be prepared by other methods including ultrasonication and in situ emulsification.¹¹

Ultrasonic emulsification:

Ultrasonic emulsification reduces droplet size pretty effectively. Sonotrodes known as sonicator probes provide the energy needed for ultrasonic emulsification. It contains a piezoelectric quartz crystal, which contracts and expands in response to an alternating electric voltage. Hence, ultrasonography can be used directly to make emulsion; this technique is mostly used in laboratory settings where emulsion droplet sizes as fine as 0.2 micrometers can be achieved.¹²

Microfluidization:

The patented mixing method known as microfluidization involves the use of a device called a microfluidizer. High pressure is used to drive the medicinal product through the interaction chamber, resulting in submicron-sized particles. The procedure is carried out repeatedly until the required particle size is attained in order to produce a homogenous nanoemulsion.¹³

Spontaneous emulsification:

It involves these three steps: The formation of an oil-in-water emulsion (o/w) involves three steps: (a) creating a uniform organic solution of oil and lipophilic surfactant in a water-miscible solvent, (b) constantly mixing the organic phase into the aqueous phase, and (c) eliminating the aqueous phase through evaporation at low pressure¹⁴.

Solvent evaporation technique/hydrogel method:

Using this procedure, a drug solution is made, emulsified with a liquid (not the drug's solvent), and the drug is precipitated by evaporating the solvent. One way to regulate crystal formation and particle aggregation is with a high-speed stirrer. There are several similarities between the solvent evaporation approach and the hydrogel method. The sole difference between this case from the solvent evaporation procedure is that the drug solution is miscible with the drug antisolvent.¹⁵

Additives and Functionalization:

To impart desired functions or improve stability, nanoemulsions may contain additional additives in addition to surfactants and co-surfactants. Antioxidants, antimicrobials, viscosity modifiers, and functional payloads like medications or bioactive substances are a few examples of these additions.

FACTORS TO BE CONSIDERED DURING PREPARATION OF NANOEMULSION:

1. In order to produce ultralow interfacial tension, which is necessary for the creation of nanoemulsion, the surfactant has to be carefully selected.

2. A sufficiently high concentration of surfactant is required to stabilize the microdroplets and form a nanoemulsion.

3. The surfactant needs to be sufficiently flexible or fluid to promote the formation of nanoemulsions¹⁶.

Emerging Trends and Innovations:

Novel methodologies and tactics have emerged in recent years to improve efficiency, scalability, and sustainability of nanoemulsion formulation. These include the production of nanoemulsions with exact control over droplet size, distribution, and composition through the use of green synthesis techniques, microfluidics, and electrospinning. Moreover, functionalizing nanoemulsions and increasing their uses in targeted medication delivery, sensing, and imaging are potential benefits of integrating nanomaterials like nanoparticles and nanofibers. To put it briefly, creating stable dispersions with certain qualities requires a variety of steps in the formulation process, including choosing the right ingredients, applying formulation processes, and adding additives. Through comprehension of the fundamental concepts and utilization of recent advancements, scientists and producers can fully unleash the capabilities of nanoemulsions in a variety of uses.

CHARACTERIZATION OF NANOEMULSIONS:

A stable nanoemulsion is characterized by the absence of the internal phase, absence of creaming, absence of microbial deterioration, and retention of elegance in terms of appearance, color, odor, and consistency.¹⁷

Thus, the emulsion instability can be categorized as follows:

Flocculation and creaming:

Compared to separate globules, floccules rise or sink through the emulsion more quickly when they are mixed. We call this process flocculation. The process of scattered globules rising or descending to form a concentrated layer is called creaming. Consequently, flocculation is followed by creaming.

Cracking:

Layers of the dispersed phase separate when an emulsion fractures. While an emulsion that has fractured cannot be repaired, it can be recombined by shaking or stirring the creamed portion. An indication of persistent instability is cracking. An emulsion cracking could be caused by the following factors: First, an opposing emulgent is added; second, the emulgent breaks down or precipitates; third, a common solvent is added, in which the aqueous and oily phases are miscible; fourth, temperature extremes; fifth, microorganisms; and sixth, creaming.

Miscellaneous instability:

Emulsions can deteriorate if kept in the presence of light, at extreme temperatures, or both. Emulsions are consequently usually packaged in colored, sealed containers and kept at a reasonable temperature.

Phase inversion:

It is the conversion of an o/w emulsion to a w/o emulsion and the reverse. It is the physiological process. Phase inversion can be caused by variations in the phase volume ratio, the addition of electrolytes, and temperature changes.

EVALUATION PARAMETERS OF NANOEMULSION:

Droplet Size Analysis:

One important factor affecting the functionality, stability, and bioavailability of nanoemulsions is droplet size. Droplet size distribution is measured using a variety of methods, such as laser diffraction, dynamic light scattering (DLS), and nanoparticle tracking analysis (NTA). Because DLS is quick and non-invasive, it is frequently used to determine the average droplet size and size distribution of nanoemulsions. The size of the droplets in a nanoemulsion can also be examined using transmission electron microscopy, or TEM.¹²

Viscosity determination:

A rotational viscometer of the Brookfield type is used to measure the viscosity of nanoemulsions at different shear rates and temperatures.¹⁸

Test of Dilution:

This type of can be found by adding water or oil to a nanoemulsion to dilute it. The test is based on the finding that additional continuous phase can be introduced to a nanoemulsion without causing it to lose stability. Consequently, it is possible to dilute a w/o nanoemulsion with oil and an o/w nanoemulsion with water. Substance level of drugs. A spectrophotometer or high-performance liquid chromatography (HPLC) is used to compare the extracted preweighed nanoemulsion to a drug reference solution after it has been dissolved in an appropriate solvent¹⁹.

Efficiency of Entrapment:

Entrapment efficiency (EE%) was determined by measuring the concentration of free drug (un-entrapped) in aqueous medium. This is the prime importance, as it influences the release characteristics of drug molecule. The amount of drug encapsulated per unit weight of nanoparticles is determined after separation of the entrapped drug from the nanoemulsion formulation:

EE = Weight of total drug in formulation – Weight of drug in aqueous phase × 100/Weight of total drug in formulation²⁰

Thermodynamic stability:

The selected formulation is subjected to different thermodynamic stability tests.

Heating cooling cycle:

The temperature of refrigerators between 4° and 45° of six cycles with storage at each temperature of not less than 48hr is studied. Those formulations, which are stable at these temperatures, are subjected to centrifugation

In vitro Diffusion research:

With the help of a cellophane membrane, Franz diffusion cells are used to conduct diffusion investigations on the generated nanoemulsions²¹. A 5 milliliter nanoemulsion sample is placed on a cellophane membrane, and diffusion experiments are performed at 37±1°C using the dissolution medium, use 250milliliters of 25% methanolic phosphate buffer (pH 7.4). To maintain sink condition, 5 ml of each sample was taken out at intervals of 1, 2, 3, 4, 5, 6, 7, and 8hours. Each sample was then replaced with an equal volume of fresh dissolving medium. The drug content of samples is measured using a UV spectrophotometer at 271nm.²²

Dye test:

When a water-soluble dye is applied to an o/w nanoemulsion, the nanoemulsion absorbs the color evenly. In contrast, if the emulsion is without type and the dye is water soluble, the emulsion only absorbs the color in the dispersed phase and the color is not uniform; this can be easily observed under a microscope.

Refractive index:

The Abbes refractometer is used to determine the index of refraction of nanoemulsion.

pH:

A pH meter can be used to measure the pH of a nanoemulsion.

Measurement of Zeta Potential:

The stability and colloidal behavior of nanoemulsion droplets are significantly influenced by their zeta potential, which is a reflection of their surface charge. Zeta potential is measured using methods like electrophoretic light scattering and laser Doppler velocimetry, which provide insight into the electrostatic repulsion between charged droplets and forecast their stability against aggregation and coalescence. High absolute zeta potential values (>30mV) are generally indicative of improved dispersion stability and electrostatic stabilization. Zeta PALS is the equipment used to measure zeta potential. It is employed to quantify the charge on a droplet's surface in a nanoemulsion.²³

Scanning Electron Microscopic Analysis:

The versatile device known as the scanning electron microscope (SEM) is used for material characterization. A relatively low energy focused electron beam is utilized to create an image. This method makes it possible to comprehend the structural and morphological changes brought on by cell damage in the pathogen's cell membrane. Interaction with the nanoemulsion is noted, and the sample is SEM-examined²⁴.

Test for fluorescence:

Many oils glow in the presence of UV light. When a fluorescent light is shone on a w/o nanoemulsion, the entire field fluoresces under a microscope. If the fluorescence is irregular, the o/w type nanoemulsions is employed.

Percentage transmittance:

A UV visible spectrophotometer is used to determine the nanoemulsion's percentage transmittance.

Test of Spreadability:

The spreadability device, which included two glass slides and a wooden board with a scale, is used to measure spreadability. Determining the region that the formulation might freely distribute over the skin's afflicted area after application is helpful. A single gram of gel, emulgel, or nanoemulgel formulation was sandwiched between two 25cm by 25cm horizontal glass slides, together with a 500g load was used for a minute. Since it indicates the spreadability value, the diameter of the formulations' spread is measured.²⁵

Filter paper test:

This test is based on the fact that an o/w nanoemulsion spreads out quickly when placed onto filter paper. In comparison, a w/o nanoemulsion will move very slowly. This method should not be used on very viscous creams. The optimized nanoemulsions underwent six cycles of the heating-cooling test and three cycles of the freeze-thaw test.²⁶

Rheological Characterization:

The application performance, stability, and flow behavior of nanoemulsions are influenced by their rheological properties. In rheological characterization, variables like viscosity, viscoelasticity, and shear thinning behavior are evaluated by the use of oscillatory and rotational rheometry techniques. These metrics shed light on the internal composition. The flow characteristics of nanoemulsions, directing the creation of formulations for uses like topical formulations or injectable medication delivery systems that call for particular rheological profiles²⁷.

Stability Studies:

Accelerated stability tests are carried out to replicate environmental conditions and evaluate the long-term stability of nanoemulsions. These studies include centrifugation, freeze-thaw cycles, and thermal stress testing. It is necessary to track changes in droplet size, zeta potential, and appearance in order to pinpoint destabilizing causes and guide formulation optimization initiatives. The principles underlying emulsion destabilization mechanisms are explained in this part, which also methodically lays out the reasons for the strong stability of nanoemulsions.²⁸

Methods of Spectroscopy:

Spectroscopic methods including fluorescence spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) provide understanding of the structural characteristics and molecular interactions of nanoemulsions. To sum up, characterization approaches are essential for clarifying the physicochemical, structural, and functional characteristics of nanoemulsions, which helps with formulation optimization and performance evaluation. Through the application of a range of complimentary methodologies, scientists can acquire a thorough understanding of the behaviour and stability of nanoemulsions, which opens up new avenues for their efficient use in a variety of applications²⁹.

In vitro drug release:

To assess and identify the formulation that releases the greatest quantity of drug release from the nanoemulsion formulation, in vitro drug release for the nanoemulsion formulation should be performed.³⁰ application across several channels

1. Oral delivery of nanoemulsions containing drugs

2. Parenteral medication delivery methods based on nanoemulsion

3. The use of nanoemulsions in medication transdermal delivery

4. The intranasal method of medication administration

5. Additional drug delivery routes: It comprises the cytosolic drug delivery system and the ocular channel.³¹ This examines the wide range of uses for nanoemulsions that leverage their adaptability in the fields of pharmaceuticals, cosmetics, food and agriculture³².

PHARMACEUTICAL APPLICATIONS:

By facilitating enhanced solubility, bioavailability, and targeted distribution, nanoemulsions provide pharmaceutical actives a promising new delivery mechanism. Nanoemulsions improve therapeutic efficacy and reduce negative effects by facilitating the regulated release and encapsulation of hydrophobic and hydrophilic medicines in medication delivery. Applications for them include cancer therapy, antimicrobial treatment³³, and vaccine administration. Antigens are frequently loaded into nanocarriers by physical adsorption, encapsulation (with or without coating and targeting), and conjugation (with chemical or targeting) processes. Antigens are enclosed in nanocarriers in any of the mechanisms.³⁴

Cosmetics and Personal Care Products:

By offering improved stability, skin penetration, and sensory qualities, nanoemulsions provide adaptable solutions for cosmetics and personal care products. Nanoemulsions enhance the efficacy and skin benefits of skincare formulations by facilitating the encapsulation and transport of active compounds like vitamins, antioxidants, and anti-aging agents. They are also used in hair care products, sunscreen formulations³⁵, and color cosmetics, where they provide better UV protection and lightweight, non-greasy textures.

Food and Beverage Sector:

The food and beverage sector relies heavily on nanoemulsions, beverage business, providing solutions for shelf-life extension, vitamin fortification, and flavor encapsulation. By enhancing the solubility and bioavailability of lipophilic bioactive ingredients like vitamins, antioxidants, and essential oils in food formulations, nanoemulsions facilitate the better incorporation of these ingredients into functional meals and beverages. They are also used to increase texture, mouth feel, and sensory qualities in emulsified goods, salad dressings, dairy products, and baked goods³⁶.

Essential Oil Nanoemulsions in Food Preservation:

Plant-derived essential oils have strong antibacterial activity against a variety of foodborne pathogens. Strong antibacterial properties make essential oils like thyme, oregano, clove, and orange, as well as their constituents like thymol, carvacrol, eugenol, limonene, and cinnamon, useful as natural preservatives. However, owing of their lipophilic nature, their use in food is limited. Here, the poor solubility problem can be solved by using nanoemulsions. Foods can effectively use encapsulated essential oils in nanoemulsions as natural preservatives.³⁷

Functional foods and nutraceuticals:

Lipophilic compounds can be encapsulated using nanoemulsions in nutraceutical formulations improvement. Essential Oil using nanoemulsions to preserve food, Plant-derived essential oils have strong antibacterial activity against a variety of foodborne pathogens. Foods can effectively use encapsulated essential oils in nanoemulsions as natural preservatives.²⁶ Nanoemulsions facilitate the encapsulation of lipophilic vitamins, omega-3 fatty acids, and phytochemicals in nutraceutical formulations, thereby augmenting their absorption and activity within the body. They are used in functional food products, fortified drinks, and dietary supplements that target a range of health benefits, such as immune system support, cardiovascular health and cognitive performance.

DISCUSSION:

Nanoemulsions have become highly adaptable platforms with a wide range of uses in food, agriculture, cosmetics, pharmaceuticals, and other fields. We address the main conclusions and revelations from our in-depth analysis of nanoemulsions in this conversation, as well as the prospects, problems, and potential paths forward in this quickly developing sector.

Formulation Challenges and Strategies:

The creation of nanoemulsions poses a number of difficulties, such as stabilization, obtaining the ideal droplet size distribution, as well as scalability. While traditional methods of producing nanoemulsions, such high-pressure homogenization and ultrasonication, are effective, creative solutions are required to deal with problems like batch-to-batch unpredictability and energy usage. New approaches like green synthesis and microfluidics have the potential to improve formulation sustainability and efficiency by providing fine control over droplet composition and size.

Techniques for Characterization and Their Limitations:

The properties and behavior of nanoemulsions are clarified by characterization techniques, which also direct efforts at formulation improvement and quality control. Nevertheless, there are obvious drawbacks, especially when evaluating intricate nanoemulsion systems in practical matrices. These constraints might be solved by future developments in characterisation methodology, such as the creation of multi-modal approaches and in situ imaging techniques, which would offer deeper insights into the behavior of nanoemulsions in a changing environment.

Applications and Market Trends:

Nanoemulsions are used in a wide range of industries, including food, agriculture, environmental remediation, personal care, and healthcare. Even while using nanoemulsions for targeted medicine delivery, improved nutrition, and sustainable agriculture has advanced significantly, there is still unrealized promise in new fields including textile coatings, energy storage, and environmental cleanup. The market is showing signs of increasing demand for goods based on nanoemulsions due to consumer preferences for increased safety, sustainability, and efficacy.

FUTURE PROSPECTS AND OPPORTUNITIES:

Looking ahead, a number of interesting directions for more study and advancement with nanoemulsions become apparent. Personalized nanoemulsion-based therapeutics, the investigation of synergistic formulations for multimodal drug delivery, and the integration of advanced materials with nanotechnology for tailored functionality are a few examples. Furthermore, developments in machine learning, artificial intelligence, and computer modeling may speed up formulation optimization and improve the accuracy of behaviour predictions for nanoemulsions. To sum up, nanoemulsions are a flexible and exciting platform with broad applications in a variety of industries. Through the resolution of formulation issues, advancement of characterisation methods, management of regulatory issues, and seizing new chances, Nanoemulsions have become a highly adaptable and promising platform with a wide range of applications in food, agriculture, cosmetics, pharmaceuticals, and other fields. We have explored the formulation, characterisation, uses, and future prospects of nanoemulsions through our thorough review, navigating their complex landscape. We have examined the complex procedures and essential elements for creating stable nanoemulsions in formulation, emphasizing the significance of surfactants, co-surfactants, and formulation methods such phase inversion, high-pressure homogenization, and ultrasonication. The properties and behavior of nanoemulsions are crucially explained by characterization techniques, which also direct efforts towards formulation improvement and quality control. Based on zeta potential and droplet size analysis a wide range of procedures, from measurement to rheological characterisation and imaging techniques, provide insights into the stability, performance, and interactions of nanoemulsions in complicated matrices.. Personalized nanoemulsion-based therapeutics, the investigation of synergistic formulations for multimodal drug delivery, and the integration of advanced materials with nanotechnology for tailored functionality are a few examples. The proliferation of nanoemulsion-based products in several industries has led to a growing importance of regulatory considerations including safety, efficacy, and labeling. uniformity. In the quickly growing nanoemulsion sector, testing procedures, safety threshold establishment, and open labeling standards are critical to maintaining customer trust and regulatory compliance. To sum up, nanoemulsions are a flexible and exciting platform with broad applications in consumer goods, healthcare, and environmental sustainability. Through the resolution of formulation issues, advancements in characterization methods, navigation of regulatory issues, and seizing new opportunities, scholars and industry players can fully utilize nanoemulsions to tackle urgent global issues and enhance human health, well-being, and sustainability.

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Received on 22.08.2024 Revised on 19.12.2024

Accepted on 01.02.2025 Published on 18.04.2025

Available online from April 22, 2025

Asian J. Res. Pharm. Sci. 2025; 15(2):199-206.

DOI: 10.52711/2231-5659.2025.00031

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