Stable Multiple Emulsions Research Articles

The Composition Optimization of Curcumin-Loaded Double Oil-Water-Oil Emulsions and Their Stability Evaluation.

This study aimed to optimize the preparation of multiple oil-water-oil (O/W/O) emulsions using varying amounts of Tween 20 emulsifier, different homogenization methods, and optimal preparation temperatures as carriers for encapsulated curcumin. Following the optimization process, the optimal preparation temperature was found to be 25 °C, with a homogenization speed of 10,000 RPM and an emulsifier concentration of 0.5% Tween 20. Subsequently, the effects of physicochemical and viscoelastic properties on the different types of oils used in the outer phase, as well as the impact of storage time, were monitored. The novelty of this work lies in its comprehensive analysis of the stability and encapsulation efficiency of multiple emulsions using various oils, an area that has not been extensively explored before. After identifying the optimal preparation procedure, all samples with different edible oils demonstrated excellent stability and encapsulation efficiency, showing minimal variation in results. The most stable multiple emulsion was found to be the one with coconut oil in the outer phase, exhibiting half the particle size compared to other samples and the lowest encapsulation efficiency losses over 50 days of storage. This study provides new insights into the formulation of stable multiple emulsions for the effective delivery of curcumin and similar bioactive compounds.

Formulation and Characterization of Double Emulsions W/O/W Stabilized by Two Natural Polymers with Two Manufacturing Processes (Comparative Study)

Four distinct types of multiple emulsions were synthesized using xanthan gum and pectin through two distinct manufacturing processes. The assessment encompassed the examination of morphology, stability, and rheological properties for the resulting water-in-oil-in-water (W/O/W) double emulsions. Formulations were meticulously crafted with emulsifiers that were compatible with varying compositions. Remarkably stable multiple emulsions were achieved with a 0.5 wt% xanthan concentration, demonstrating resilience for nearly two months across diverse storage temperatures. In contrast, multiple emulsions formulated with a higher pectin concentration (2.75 wt%) exhibited instability within a mere three days. All multiple emulsions displayed shear-thinning behavior, characterized by a decline in apparent viscosity with escalating shear rates. Comparatively, multiple emulsions incorporating xanthan gum showcased elevated viscosity at low shear rates in contrast to those formulated with pectin. These results underscore the pivotal role of the stepwise process over the direct approach and emphasize the direct correlation between biopolymer concentration and emulsion stability. This present investigation demonstrated the potential use of pectin and xanthan gum as stabilizers of multiple emulsions with potential application in the pharmaceutical industry for the formulation of topical dosage forms.

Характеристика емульсій «вода в кам'яновугільній смолі», стабілізованих пилоподібною вугільною речовиною

CHARACTERIZATION OF "WATER IN COAL TAR" EMULSIONS STABILIZED WITH PULVERIZED COAL MATTER © L.P. Bannikov, PhD in Technjcal Sciences (State Enterprise "Ukrainian State Scientific Research Institute of Coal Chemistry (UKHIN), 7 Vesnina str., Kharkiv, 61023, Ukraine) Difficulties in dehydrating coal tar, especially those with a high degree of pyrolysis, are associated with the complex nature of numerous intermolecular interactions that provide high viscosity of the dispersion medium. On the other hand, emulsions are stabilized by dispersed particles insoluble in toluene and quinoline. However, the most distinctive feature is the stabilization of water droplets by the particles of the coke oven carry–over. First of all, the carry–over is related to the chamber loading process as well as the steam and hydro injection used. This leads to the absorption of the smallest dust particles by the condensing tar. The presence of functional groups in the coal substance gives hydrophilicity to the generally hydrophobic conventional coal molecule. In addition, the mineral part of coal also contributes to the diffusivity of the substance, which makes it surface active and capable of stabilizing emulsions. It has been shown that such particles are capable of forming stable multiple emulsions, which, as is known from the experience of oil dehydration, are very stable. The formation of emulsions was carried out on a mechanical stirrer, samples of crushed coking coal were used as emulsifiers, clay and sand were taken as a hydrophilic standard, and industrial soot was used as a hydrophobic standard. The maximum volume of the emulsion was obtained when "Zh" coal and "OS" coal were used as a powder emulsifier. The minimum volume of the emulsion was formed when hydrophilic components, such as sand and clay, were introduced into the system. The formation of multiple emulsions of the "tar in water/water in tar" type was noted. With an increase in the degree of hydrophobicity of powdered emulsifiers, the droplet size decreases, the interfacial surface increases, and the emulsion becomes more stable. The emulsifying ability of powders is explained by the formation of a structural and mechanical barrier. Keywords: coal tar, quinoline-insoluble substances, coal substance, stabilizers, hydrophilicity, hydrophobicity, multiple emulsions. Corresponding author: Bannikov Leonid P., e-mail: ukhinbannikov@gmail.com

Formulation and Evaluation of Multiple Emulsion of Repaglinide

Repaglinide (Prandin) is an oral insulin secretagogue of the meglitinide class (Antidiabetic) of BCS Class ІІ has low bioavailability. It is used to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood). The Multiple Emulsion is the complex polydispersed system in which an emulsion is incorporated in another emulsion therefore they are also known as “Emulsion of Emulsion”. The aim was to prepare a stable Multiple Emulsion of Repaglinide by incorporating various hydophilic and lipophilic surfactants at different concentrations. The characterization of drug sample was done using spectrophotometric analysis and melting point determination. All the observations and recorded data were identical to the values reported in literature. Calibration curves of Repaglinide in 0.1N HCl and phosphate buffer (pH 7.4) were prepared using a double beam UV-visible spectrophotometer (Shimadzu 1800)The different formulations of multiple emulsion were evaluated on the basis of their drug entrapment efficiency and stability. The multiple emulsion was stable and had good entrapment efficiency. There were no drug-excipients interactions. From the result and conclusion of the research work we can summarize that the multiple emulsions can be optimized for good stability and higher entrapment efficiency by optimizing different formulation variables like type and proportion of primary and secondary emulsifier incorporated in Primary Emulsion and Multiple Emulsion.

Development of Niacinamide/Ferulic Acid-Loaded Multiple Emulsion and Its In Vitro/In Vivo Investigation as a Cosmeceutical Product.

Objective Multiple emulsions have the ability to incorporate both lipophilic and hydrophilic actives in the same preparation and facilitate permeation of active ingredients through skin. The current study was aimed at formulating niacinamide/ferulic acid-loaded stable multiple emulsion (MNF) and its in vitro/in vivo characterization as a cosmeceutical product. Methods Both the compounds were evaluated for their radical scavenging potential by the DPPH method and FTIR analysis. Then, placebo and active formulations were prepared using a double emulsification method and were investigated for stability testing (changes in color, odor, and liquefaction on centrifugation, pH, and globule size) for a period of three months. Afterwards, MNF was investigated for in vitro sun protection factor, rheological studies, entrapment efficiency, zeta potential, zeta size, and ex vivo permeation. Moreover, after ensuring the hypoallergenicity and safety, it was also checked for its cosmeceutical effects on human skin using noninvasive biophysical probes in comparison with placebo. Results Results demonstrated that MNF showed a non-Newtonian behavior rheologically and both MNF and placebo were stable at different storage conditions. Entrapment efficiency, zeta potential, and zeta size were 93.3%, -5.88 mV, and 0.173 μm, respectively. Moreover, melanin, sebum, and skin erythema were significantly reduced while skin elasticity and hydration were improved. Conclusion It is evident that niacinamide and ferulic acid can be successfully incorporated in a stable multiple emulsion which has potent cosmeceutical effects on human skin.

Preparation of stable multiple emulsions using food-grade emulsifiers: evaluating the effects of emulsifier concentration, W/O phase ratio, and emulsification process

In this study, the effects of sodium caseinate (NaCN; emulsifier) concentration, a type of hydrophilic emulsifier, as well as concentration of primary W/O emulsion on the stability of water–oil-water (W/O/W) emulsions were investigated. Emulsions were made using two different emulsification techniques including ultrasonic liquid processing and high pressure homogenization (HPH). Microscopy images of W/O/W emulsions in combination with droplet size analysis and viscosity measurements showed that the sample with a higher percentage of primary W/O emulsion (50 wt% vs. 40 wt% and 25 wt%) was more resistant to coalescence (narrower droplet size distribution and lower creaming index). The higher stability of this emulsion at 50 wt% is due to the enhancement in the solution viscosity which slows down the coalescence and destabilization kinetics. The increase in the NaCN concentration from 0.3 wt% to 0.9 wt% (based on total weight of emulsion) led to formation of larger droplets possibly due to the destabilization of primary W/O emulsion through the disruption of polyglycerol polyricinoleate (PGPR) layer. Regarding the effect of emulsifier type, incorporation of Cremophor EL and Tween 60 in comparison with NaCN resulted in formation of smaller droplet size due to their enhanced surface activity at the interface. Finally, we found that using high pressure homogenizer (HPH) instead of ultrasonic processor was detrimental to the emulsion stability and size distribution. These findings further provide new pathways to design emulsion systems for food and drug delivery applications.

Development of topical drug delivery system with Sphaeranthus indicus flower extract and its investigation on skin as a cosmeceutical product.

Cosmetics are the products used to beautify the skin. Emulsion is a fine dispersion of two or more immiscible liquids. Sphaeranthus indicus is claimed to be used for skin beautification in folk medicine. Multiple emulsion was formulated containing the extract of S indicus flowers. This research study indicates that extract of S indicus flowers contains sufficient amount of polyphenols and also possess good antioxidant activity with mushroom tyrosinase inhibition activity. Further, stable multiple emulsion was developed and stability testing was performed for 180days by keeping the multiple emulsion at 8°C±1, 25°C±1, 40°C±1, and 40°C±1 with 75%±1 RH. Parameters checked were color change, phase distribution, viscosity, droplet size and size distribution, pH determination, and electrical conductivity. Sun protection factor (SPF) was determined which also showed promising results. Skin testing on human volunteers was done for 3months after biosafety profiling of the most stable multiple emulsion. This also showed remarkable effects. Skin erythema, melanin, and sebum were reduced. Skin hydration and elasticity were increased. There was also reduction in the number of skin large and small skin pores. Skin spot area was also reduced by the use of multiple emulsion loaded with S indicus flower extract. ANOVA test showed that all the effects produced on skin were significant, ie, P≤.05. A stable multiple emulsion was developed which produced significant cosmetic effects on human skin.

Recent Trends in Multiple Emulsion-A Comprehensive Review

Multiple emulsions are complex polydispersed systems where both oil in water and water in oil emulsion exists concurrently which are stabilized by lipophillic and hydrophilic surfactants respectively. The ratio of these surfactants is important in achieving stable multiple emulsions. Among water-in-oil-in-water (w/o/w) and oil-inwater-in-oil (o/w/o) type multiple emulsions; the previous has wider areas of application. Formulation, preparation techniques and in vitro characterization methods for multiple emulsions are reviewed. It finds extensive range of applications in controlled or sustained drug delivery, targeted delivery, taste masking, bioavailability improvement, enzyme immobilization, etc. Multiple emulsions have also been employed as transitional step in the microencapsulation process and are the systems of increasing interest for the oral delivery of hydrophilic drugs, which are unbalanced in gastrointestinal tract like proteins and peptides Preparation of monodispersed multiple emulsion is important in DDS to improve their stability and to facilitate control of their properties. The study concluded that stable multiple emulsion with high entrapment efficiency can be prepared by two step emulsification method using Spans40, 60, 80 as primary emulsifier and Tween80 as secondary emulsifier.

Effect of surfactants and gelatin on the stability, rheology, and encapsulation efficiency of W1/O/W2 multiple emulsions containing avocado oil

AbstractThe main aim of this study was to determine the effect of emulsifiers on the stability, rheology. and encapsulation efficiency of W1/O/W2 multiple emulsions, which contain avocado oil and NaCl encapsulated. The primary emulsion contained 5 or 6 wt % polyglycerol polyricinoleate (PGPR) and 3 or 4 wt % gelatin, and the secondary emulsion contained 2 wt % Tween 40 or Tween 80. Each of the emulsions prepared presented non‐Newtonian shear thinning and concentrate solution behavior at 25 °C. Emulsions containing Tween 40 had a higher stability than those containing Tween 80. The best encapsulation efficiency was obtained for the emulsion containing 6 wt % PGPR, 3 wt % gelatin, and 2 wt % of Tween 40, which retained 92% of NaCl in the inner aqueous phase after 20 days of storage at 4 °C. Therefore, the use of Tween 40 combined with PGPR and gelatin has great potential to form stable multiple emulsions. Furthermore, emulsions combined with avocado oil can be associated with health benefits.Practical applicationsThis article presents a study on the effects of stabilizer concentrations on some properties of multiple emulsions prepared with avocado oil. Tween 40 was used as secondary emulsifier and was found to be a good alternative to Tween 80, one of the most commonly used emulsifiers in the food industry. Besides that, avocado oil has a great potential as food ingredient, due to its health benefits, but is scarcely used and studied. The characterization of multiple emulsions is presented along with a proposal of using them in the production of several food products.

Multiple Water-in-Oil-in-Water Emulsion Gels Based on Self-Assembled Saponin Fibrillar Network for Photosensitive Cargo Protection.

A gelled multiple water-in-oil-in-water (W1/O/W2) emulsion was successfully developed by the unique combination of emulsifying and gelation properties of natural glycyrrhizic acid (GA) nanofibrils, assembling into a fibrillar hydrogel network in the continuous phase. The multiple emulsion gels had relatively homogeneous size distribution, high yield (85.6-92.5%), and superior storage stability. The multilayer interfacial fibril shell and the GA fibrillar hydrogel in bulk can effectively protect the double emulsion droplets against flocculation, creaming, and coalescence, thus contributing to the multiple emulsion stability. Particularly, the highly viscoelastic bulk hydrogel had a high storage modulus, which was found to be able to strongly prevent the osmotic-driven water diffusion from the internal water droplets to the external water phase. We show that these multicompartmentalized emulsion gels can be used to encapsulate and protect photosensitive water-soluble cargos by loading them into the internal water droplets. These stable multiple emulsion gels based on natural, sustainable saponin nanofibrils have potential applications in the food, pharmaceutical, and personal care industries.

Multilamellar Thermoresponsive Emulsions Stabilized with Biocompatible Semicrystalline Block Copolymers.

We demonstrate specific interface-templated crystallization behavior of biocompatible amphiphilic poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) block copolymers enabling triggered shaping of the curvature of the oil/water interface and controlled phase inversion, including the formation of stable multiple emulsions. Water-born anisotropic micelles of PEO-b-PCL block copolymers self-assemble at the oil-water interface in a multilayer form and undergo conformational rearrangements into unique semicrystalline multilamellar shells, for which curvature (type of emulsion) can be tuned by the molecular architecture (volume fractions of the blocks) and/or by the temperature. The latter trigger affects both the solubility of the PEO block in water and the semicrystalline state of the PCL block. Remarkably, multilamellar semicrystalline shells provide both long-term stability and enhanced barrier properties of toluene-water emulsions, as well as the fast change of the bending, leading to thermo-induced phase inversion. These findings signify the development of novel practical mechanisms for controlled triggered encapsulation and release systems.

One-step formation of multiple Pickering emulsions stabilized by self-assembled poly(dodecyl acrylate-co-acrylic acid) nanoparticles.

In this study, a one-step generation of stable multiple Pickering emulsions using pH-responsive polymeric nanoparticles as the only emulsifier was reported. The polymeric nanoparticles were self-assembled from an amphiphilic random copolymer poly(dodecyl acrylate-co-acrylic acid) (PDAA), and the effect of the copolymer content on the size and morphology of PDAA nanoparticles was determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The emulsification study of PDAA nanoparticles revealed that multiple Pickering emulsions could be generated through a one-step phase inversion process by using PDAA nanoparticles as the stabilizer. Moreover, the emulsification performance of PDAA nanoparticles at different pH values demonstrated that multiple emulsions with long-time stability could only be stabilized by PDAA nanoparticles at pH 5.5, indicating that the surface wettability of PDAA nanoparticles plays a crucial role in determining the type and stability of the prepared Pickering emulsions. Additionally, the polarity of oil does not affect the emulsification performance of PDAA nanoparticles, and a wide range of oils could be used as the oil phase to prepare multiple emulsions. These results demonstrated that multiple Pickering emulsions could be generated via the one-step emulsification process using self-assembled polymeric nanoparticles as the stabilizer, and the prepared multiple emulsions have promising potential to be applied in the cosmetic, medical, and food industries.

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches.

Multiple emulsions have great potential for application in food science as a means to reduce fat content or for controlled encapsulation and release of actives. However, neither production nor stability is straightforward. Typically, multiple emulsions are prepared via two emulsification steps and a variety of approaches have been deployed to give long-term stability. It is well known that multiple emulsions can be prepared in a single step by harnessing emulsion inversion, although the resulting emulsions are usually short lived. Recently, several contrasting methods have been demonstrated which give rise to stable multiple emulsions via one-step production processes. Here we review the current state of microfluidic, polymer-stabilized and particle-stabilized approaches; these rely on phase separation, the role of electrolyte and the trapping of solvent with particles respectively.

Oil-in-oil emulsions stabilised solely by solid particles.

A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil-oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

Optimization and development of stable w/o/w cosmetic multiple emulsions by means of the Quality by Design approach.

The aim of our present work was to develop stable water-in-oil-in-water (w/o/w) cosmetic multiple emulsions that are proper for cosmetic use and can also be applied on the skin as pharmaceutical vehicles by means of Quality by Design (QbD) concept. This product design concept consists of a risk assessment step and also the 'predetermination' of the critical material attributes and process parameters of a stable multiple emulsion system. We have set up the hypothesis that the stability of multiple emulsions can be improved by the development based on such systematic planning - making a map of critical product parameters - so their industrial usage can be increased. The risk assessment and the determination of critical physical-chemical stability parameters of w/o/w multiple emulsions to define critical control points were performed by means of quality tools and the leanqbd(™) (QbD Works LLC, Fremont, CA, U.S.A.) software. Critical materials and process parameters: Based on the results of preformulation experiments, three factors, namely entrapped active agent, preparation methodology and shear rate, were found to be highly critical factors for critical quality attributes (CQAs) and for stability, whereas the nature of oil was found a medium level risk factor. The results of the risk assessment are the following: (i) droplet structure and size distribution should be evaluated together to be able to predict the stability issues, (ii) the presence of entrapped active agents had a great impact on droplet structure, (iii) the viscosity curves represent the structural changes during storage, if the decrease in relative viscosity is >15% the emulsion disintegrates, and (iv) it is enough to use the shear rate between 34g and 116g relative centrifugal force (RCF). CQAs: By risk assessment, we discovered that four factors should be considered to be high-risk variables as compared to others: droplet size, droplet structure, viscosity and multiple character were found to be highly critical attributes. The preformulation experiment is the part of a development plan. On the basis of these results, the control strategy can be defined and a stable multiple emulsion can be ensured that meets the relevant stakeholders' quality expectations.

Multiple W/O/W emulsions as dermal peptide delivery systems

Dermal delivery of peptides is a difficult task that needs to be solved by formulators in the pharmaceutical as well as in the cosmetic industry. Since multiple W/O/W emulsions are interesting vehicles for delivery of peptides, the influences of different plant-derived oils, namely avocado, wheatgerm and olive oil, on the formation and properties of multiple emulsions were investigated. The multiple W/O/W emulsions were characterized in terms of long-term stability, rheological properties, droplet size and internal structure. Moreover, the in vitro skin permeation of acetyl hexapeptide-8 (AH-8) from the multiple emulsions was investigated by Franz-type diffusion cells with porcine skin. The use of olive oil led to the most stable multiple emulsion with enhanced skin permeation of AH-8 compared to the other multiple emulsions. Moreover, a significantly increased skin permeation of AH-8 at acidic compared to physiological conditions revealed a strong dependency of AH-8 permeation on the chosen pH value.

Preliminary 1 month stability screening of cosmetic multiple emulsions (W/O/W) prepared using cetyl dimethicone copolyol and Polysorbate 80.

The objective of this work was to develop W/O/W emulsions with different concentration of paraffin oil, lipophilic (cetyl dimethicone copolyol) and hydrophilic emulsifiers (polysorbate 80) and to check their stability at different storage conditions. Approximately, 20 formulations (W/O/W) multiple emulsions were prepared, and their stability was checked at different storage conditions for the period of 30days. Stability of some multiple emulsions ME12, ME13, ME14, ME19 and ME20 was also checked with carbomer as viscosity-enhancing agent. Microscopic analysis for droplet size determination and rheological characterization of most stable multiple emulsions, that is, ME20 were also performed. It was observed that stability of multiple emulsion increases with the addition of gelling agent. Formulation (ME20) with 13.6% paraffin oil, 2.4% cetyl dimethicone copolyol and 0.8% polysorbate 80 was found more stable at 25°C and 40°C for the period of 30 days. Rheological analysis indicated a decrease in viscosity with the passage of time, while droplet size analysis indicated an increase in droplet size with the passage of time. As a conclusion of this work, a stable multiple emulsion with 13.6% paraffin oil, 2.4% cetyl dimethicone copolyol and 0.8% polysorbate 80 can be formulated and can be further studied for any active ingredient for cosmetic purposes.

One-step encapsulation and triggered release based on Janus particle-stabilized multiple emulsions.

One-step formation of stable multiple emulsions is demonstrated using stimuli-responsive amphiphilic Janus particles as emulsifiers. Multiple emulsions stabilized by these stimuli-responsive Janus particles can be induced to release the encapsulant by simply increasing the pH of the continuous phase.

Influence of asymmetric ratio of amphiphilic diblock copolymers on one-step formation and stability of multiple emulsions

Multiple emulsions have attracted significant interests for fundamental study and practical applications. However, the preparation of stable multiple emulsions is difficult in general because the emulsification often involves a two-step process as well as two kinds of surfactants are needed to stabilize the two thermodynamically unstable interfaces. Recently, we described a one-step inversion approach for fabricating multiple emulsions with long-term stability by using a precisely defined amphiphilic copolymer, poly(ethylene glycol)-b-polystyrene (PEG-b-PS), as sole surfactant. Herein we examine the correlation of the nature of this block copolymer with its emulsification performance in more details. Our result shows that the asymmetric ratio, namely the ratio of block length between PS and PEG of the synthesized diblock copolymer, has a great influence on the catastrophic phase inversion as well as the type and stability of the resulting emulsions. The symmetric block copolymer with the asymmetric value close to 1 can lead to stable multiple emulsions because they might have the highest surface covering density not only at the oil-in-water (O/W) normal emulsion interface, but also at the water-in-oil (W/O) inverse emulsion interface. For highly asymmetric block copolymer like PEG45-b-PS150, only W/O emulsion is obtained as the longer PS block will increase the hydrophobicity of the polymer and then it will be preferentially wetted by oil. However, for asymmetric PEG45-b-PS6 block copolymer with shorter PS block, it leads to very different catastrophic phase inversion depending on whether the micelles are formed in the aqueous phase.

Interfacial film stabilized W/O/W nano multiple emulsions loaded with green tea and lotus extracts: systematic characterization of physicochemical properties and shelf-storage stability.

Background and aimsMultiple emulsions have excellent encapsulating potential and this investigation has been aimed to encapsulate two different plant extracts as functional cosmetic agents in the W/O/W multiple emulsions and the resultant system’s long term stability has been determined in the presence of a thickener, hydroxypropyl methylcellulose (HPMC).MethodsMultiple W/O/W emulsions have been generated using cetyl dimethicone copolyol as lipophilic emulsifier and a blend of polyoxyethylene (20) cetyl ether and cetomacrogol 1000® as hydrophilic emulsifiers. The generated multiple emulsions have been characterized with conductivity, pH, microscopic analysis, phase separation and rheology for a period of 30 days. Moreover, long term shelf-storage stability has been tested to understand the shelf-life by keeping the generated multiple emulsion formulations at 25 ± 10°C and at 40 ± 10% relative humidity for a period of 12 months.ResultsIt has been observed that the hydrophilic emulsifiers and HPMC have considerably improved the stability of multiple emulsions for the followed period of 12 months at different storage conditions. These multiple emulsions have shown improved entrapment efficiencies concluded on the release rate of conductometric tracer entrapped in the inner aqueous phase of the multiple emulsions.ConclusionMultiple emulsions have been found to be stable for a longer period of time with promising characteristics. Hence, stable multiple emulsions loaded with green tea and lotus extracts could be explored for their cosmetic benefits.