Multiple Emulsion Formulations Research Articles

Rotating Membrane Emulsification for Producing Single and Multiple Emulsions

Membrane emulsification is a technique utilising a novel concept of generating droplet ‘drop by drop’ to produce emulsions. The technique has several distinctive advantages over the conventional emulsification techniques.This paper concerns on the development of membrane emulsification (Rotating Membrane Reactor, RMR) which utilizes rotating tubular membrane to initiate droplet detachments. The RMR uses a rotating stainless steel tubular membrane with laser drilled pores (100 μm pore diameter) and a syringe pump to drive the dispersed phase through the membrane at a given flow rate. O/W formulations were prepared with low viscosity of paraffin wax, two types of emulsifiers, different membrane rotation rate and dispersed phase flow rate. The emulsion droplets exhibited a coefficient of variation of 9% and 81μm droplet size. In this research, the pore size/droplet size ratio could achieve 0.8. This value was below than other membrane emulsification processes. The effects of principal system operating parameters on both the average droplet diameter and droplet uniformity were discussed. In addition, a multiple (W/O/W) emulsion formulation was investigated as well.

FORMULATION AND PHYSICAL EVALUATION OF MICROEMULSION AND W/O/W MULTIPLE EMULSIONS DOSAGE FORMS WITH ALPHA ARBUTIN, LACTIC ACID, AND NIACINAMIDE AS SKIN-WHITENING COSMETICS

Objective: The present study aimed to formulate and determine the physical stability of microemulsion and W/O/W multiple emulsions, containingα arbutin, lactic acid, and niacinamide, as skin-whitening cosmetics.Methods: A skin lightening effect can also be obtained from lactic acid, which accelerates the turnover of pigmented cells in the epidermis, andfrom niacinamide, which inhibits the transfer of melanosomes from melanocytes to keratinocytes. These active ingredients were combined inmicroemulsion and W/O/W multiple emulsions dosage forms in various concentrations of Tween 80 as an emulsifier. An evaluation and physicalstability test were carried out during 12 weeks of storage at 28±2°C, 4±2°C, and 40±2°C, as well as a cycling test.Results: The results showed that a microemulsion could be prepared in 25-35% of Tween 80 (surfactant) and 10% of ethanol (co-surfactant), andthat it had globule sizes of 2.397-16.8 nm, a transparent, pseudoplastic flow, and was most stable in storage at 28±2°C. Microemulsion with 35% ofTween 80 was the most stable microemulsion formula because it had the smallest globule size, the most stable distribution profiles of globule sizes,and the highest viscosity. W/O/W multiple emulsions could formulated made with 2.5-4.5% of Tween 80 (external emulsifier) and 3% of Span 80(internal emulsifier); these emulsions had a pseudoplastic-thixotropic flow and were most stable in storage at 28±2°C.Conclusions: The formulation of multiple emulsions with 2.5% of Tween 80 was the most stable formula, with a stable distribution profile of globulesizes during 8 weeks of storage at temperatures of 28±2°C, 4±2°C, and 40±2°C.

Macrophage Polarization and the Effect of MicroRNA-155 Administered in Water-in-Oil-in-Water Multiple Emulsion Formulations

The tumor microenvironment is composed of range of cells including macrophages that participate in sustaining tumor growth and invasion. Tumor-associated macrophages (TAM’s) polarized to the M2 or pro-tumoral phenotype are one such population of cells highly expressed in the tumor microenvironment. The expression of microRNA’s (miR’s) is often found to be dysregulated in TAM’s and hence exogenous delivery of miR provides a strategy for macrophage phenotypic modulation to attain improved anticancer activity. In this study, we assessed the use of multiple emulsions for the delivery of miR to achieve macrophage M1 repolarization. Water-in-oil-in-water (WOW) multiple emulsions (ME) were prepared using a two-step emulsification technique for encapsulation of miR-155 and cellular uptake, transfection efficiency, and repolarization capability of J774A.1 macrophages was assessed. The repolarized macrophages were co-cultured with SKOV3 ovarian cancer cells to assess the effect on macrophage morphology, motility and apoptosis of cancer cells. The ME showed enhanced uptake and expression of miR-155, which resulted in improved M1 polarization of J774A.1 cells. Co-culture studies with SKOV3 cells indicated an alteration in apoptotic profile. Holographic assessment of the co-cultured cells in real-time showed differences in motility and morphology of macrophages with miR-155 ME treated cells showing greater cellular interaction between the two phenotypes.

Biomimetic aqueous-core lipid nanoballoons integrating a multiple emulsion formulation: A suitable housing system for viable lytic bacteriophages

The emergence of antibiotic-resistant bacterial strains and the weak penetration of antibiotics into bacterial biofilms put an emphasis in the need for safe and effective alternatives for antimicrobial treatments. The application of strictly lytic bacteriophages (or phages) has been proposed as an alternative (or complement) to conventional antibiotics, allowing release of the natural predators of bacteria directly to the site of infection. In the present research effort, production of bacteriophage derivatives (starting from lytic phage particle isolates), encompassing full stabilization of their three-dimensional structure, has been attempted via housing said bacteriophage particles within lipid nanovesicles integrating a multiple water-in-oil-in-water (W/O/W) emulsion. As a proof-of-concept for the aforementioned strategy, bacteriophage particles with broad lytic spectrum were entrapped within the aqueous core of lipid nanoballoons integrating a W/O/W multiple emulsion. Long-term storage of the multiple emulsions produced did not lead to leaching of phage particles, thus proving the effectiveness of the encapsulation procedure.

Design and development of oral nanoparticulated insulin in multiple emulsion.

The present research aimed at developing an injection-free nanoparticulated formulation in multiple emulsion form, for oral delivery of insulin, which otherwise undergoes degradation in the gastric environment if administered orally. Insulin-polymeric nanoparticles were prepared using layer by layer (LbL) adsorption method and incorporated into an emulsion to form a nanoparticulated multiple emulsion. Using 0.6 M sodium chloride, the insulin nanoaggregates of 300-400 nm size were obtained about a yield of 94%. The characteristics of a representative nanoparticle were as follows: particle size - 391.9±0.41 nm, polydispersity index -0.425, zeta potential- +20.6 mv, encapsulation efficiency- 86.7±1.42% and percentage entrapment efficiency of the insulin-polymeric nanoparticles in the inner aqueous phase of emulsion was 84.6%. The FT-IR analysis confirms that there were no drug interactions with the polymers. Stability analysis carried out for 3 months at 8-40 °C, showed only minor changes at the end period. The release kinetics of the nanoparticulated multiple emulsion at pH 7.4 followed first order kinetics and obeyed the Fickian law. However, at pH 2.0 the release kinetics from nanoparticulated multiple emulsion followed zero order kinetics without obeying to the Fickian law. In conclusion, our data demonstrate that the nanoparticulated multiple emulsion formulation has good release characteristics and imparted a tolerable protection for insulin at different pH conditions, which may be exploited for oral administration.

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.

Investigation of different emulsion systems for dermal delivery of nicotinamide

Nicotinamide (NA) has been shown to have beneficial effects on several skin diseases such as tumor, acne vulgaris, photodamage, cellulite and atopic dermatitis. The purpose of this study was to develop a multiple emulsion and a microemulsion formulation as delivery systems for NA. A two-step process was used to prepare the W/O/W multiple emulsion. Optimum microemulsion formulation was selected by using construction of pseudo-ternary phase diagram. The physicochemical properties such as droplet size and viscosity measurements, stability studies were also evaluated. Ex-vivo permeation studies were performed with Franz-type diffusion cells and the samples were analysed by high performance liquid chromatography (HPLC). The permeation data showed that there was no significant difference between multiple emulsion and microemulsion (p > 0.05). Transepidermal water loss (TEWL) was also measured. As a result of TEWL studies, a slight increase of TEWL values was observed for microemulsion formulation on rat skin when compared with multiple emulsion and commercial formulation. The results suggested that microemulsion and multiple emulsion formulations could be new and alternative dosage forms for topical application of NA.

Impact of osmotic pressure and gelling in the generation of highly stable single core water-in-oil-in-water (W/O/W) nano multiple emulsions of aspirin assisted by two-stage ultrasonic cavitational emulsification

The present investigation focuses in investigating the effect of osmotic pressure, gelling on the mean droplet diameter, polydispersity index, droplet size stability of the developed novel Aspirin containing water-in-oil-in-water (W/O/W) nano multiple emulsion. The aspirin-loaded nano multiple emulsion formulation was successfully generated using two-stage ultrasonic cavitational emulsification which had been reported in author's previous study. The osmotic behavior of ultrasonically prepared nano multiple emulsions were also examined with different glucose concentrations both in the inner and outer aqueous phases. In addition, introducing gelatin into the formulation also observed to play an important role in preventing the interdroplet coalescence via the formation of interfacial rigid film. Detailed studies were also made on the possible mechanisms of water migration under osmotic gradient which primarily caused by the permeation of glucose. Besides, the experimental results have shown that the interfacial tension between the two immiscible phases decreases with varying the composition of organic phase. Although the W/O/W emulsion prepared with the inner/outer glucose weight ratio of 1–0.5% (w/w) showed an excellent droplet stability, the formulation containing 0.5% (w/w) glucose in the inner aqueous phase appeared to be the most stable with minimum change in the mean droplet size upon one-week storage period. Based on the optimization, nano multiple emulsion droplets with the mean droplet diameter of around 400nm were produced using 1.25% (w/w) Span 80 and 0.5% Cremophore EL. Overall, our investigation makes a pathway in proving that the use of ultrasound cavitation is an efficient yet promising approach in the generation of stable and uniform nano multiple emulsions and could be used in the encapsulation of various active pharmaceutical ingredients in the near future.

Short term study of human skin irritation by single application closed patch test: assessment of four multiple emulsion formulations loaded with botanical extracts

Background: Assessment of skin irritation potential is a major concern in safety assessment of cosmetics, when long-term use of these products are expected. Non-invasive bioengineering probes have been used previously to measure skin irritation potential of cosmetic ingredients.Objectives: Experimentation carried out to weigh up the skin irritation potential of four multiple emulsion formulations via visual and non-invasive measurements. Immediate effects of formulations and comparison of two assessment techniques were also tried to establish.Methods: Four multiple emulsion formulations one control (without botanical active) and three containing the functional botanical actives plus additives were tested in this study using the following techniques: transepidermal water loss (TEWL), COLIPA visual scoring method (CVSM), Mexameter MPA 5 (Courage + Khazaka, Germany) and capacitance [Corneometer MPA 5 (Courage + Khazaka, Germany)]. Visual examination and non-invasive measurements were performed at baseline and after 24 h. The formulations were applied on the forearm of 12 healthy volunteers of same sexes aged 20–25 years.Results: We found that none of the formulation produced irritation both on visual and instrumental evaluation. However, formulations MeB and MeC have comparable immediate effects on dryness, erythema, melanin and TEWL. Formulation MeC produced more effective results on different parameters, may be due to synergistic effect of two extracts, while MeA failed to produce any immediate effects on skin parameters. Moreover results of both assessment methods are parallel to each other.Conclusions: None of the formulation produce irritant effects, barrier impairment effects or immediate effects except for the formulation MeC which produced appreciable results than other formulations but statistically these results were insignificant (p > 0.05). Based on these results, it could be concluded that formulations may be implied safely as skin rejuvenating candidates.

Anti-inflammatory and analgesic activity of novel oral aspirin-loaded nanoemulsion and nano multiple emulsion formulations generated using ultrasound cavitation

The present study investigated the anti-inflammatory and analgesic activities of novel aspirin oil-in-water (O/W) nanoemulsion and water-in-oil-in-water (W/O/W) nano multiple emulsion formulations generated using ultrasound cavitation techniques. The anti-inflammatory activities of nanoemulsion and nano multiple emulsion were determined using the λ-carrageenan-induced paw edema model. The analgesic activities of both nanoformulations were determined using acetic acid-induced writhing response and hot plate assay. For comparison, the effect of pretreatment with blank nanoemulsion and reference aspirin suspension were also studied for their anti-inflammatory and antinociceptive activities. The results showed that oral administration of nanoemulsion and nano multiple emulsion containing aspirin (60mg/kg) significantly reduced paw edema induced by λ-carrageenan injection. Both nanoformulations decreased the number of abdominal constriction in acetic acid-induced writhing model. Pretreatment with nanoformulations led to a significant increase in reaction time in hot plate assay. Nanoemulsion demonstrated an enhanced anti-inflammatory and analgesic effects compared to reference suspension while nano multiple emulsion exhibited a mild inhibitory effects in the three experimental animal model tests. The results obtained for nano multiple emulsion were relatively lower than reference. However, administration of blank nanoemulsion did not alter the nociceptive response significantly though it showed slight anti-inflammatory effect. These experimental studies suggest that nanoemulsion and nano multiple emulsion produced a pronounced anti-inflammatory and analgesic effects in rats and may be candidates as new nanocarriers for pharmacological NSAIDs in the treatment of inflammatory disorders and alleviating pains.

Formulation and Evaluation of a Gel-Like Ascorbic Acid Multiple Emulsions

Abstract: Ascorbic acid is important for human, but it will be oxidized fast when dissolved in water. However, in recent years, a major breakthrough has been achieved in the preparation of w/o/w multiple emulsions containing ascorbic acid (AA). And this study shows how to prepare and evaluate the stable gel-like multiple emulsions which can be easily used in personal care products. The concentration of ascorbic acid was analyzed by UV, and the viscosity of multiple emulsions thickened with xanthan was also appraised. The retention rate of ascorbic acid in multiple emulsions was 92.4% after 30 days preparation, and it was of significance for cosmetic use.

An investigation into the mechanism of ‘spontaneous’ multiple emulsion formulation

An investigation into the mechanism of ‘spontaneous’ multiple emulsion formulation

Formulation of a Stable Multiple Emulsion via a One-Step Process Using Surface Properties of the Mixed Emulsifiers

Multiple emulsions are often stabilized using a combination of hydrophilic and hydrophobic surfactants. The ratio of surfactants is important in achieving stable multiple emulsions. The objective of this study was to investigate the influence of surface properties of mixed emulsifiers on multiple emulsion formulation and its stability. In addition, the effects of surfactant concentrations on emulsion bulk rheological properties were investigated. From the surface tension measurements, the concentrations of the two emulsifiers were deduced. A multiple emulsion was then prepared using theses quantities of surfactants via a one-step emulsification process and its stability was evaluated by investigation of the tracer release. The conductivity tests carried out to follow the release of the electrolyte, together with microscopic analyses showed that the rate of encapsulation is sensitive to emulsification conditions.

Enhanced mucosal and systemic immune response with squalane oil-containing multiple emulsions upon intranasal and oral administration in mice

The objective of this study was to develop and evaluate squalane oil-containing water-in-oil-in-water (W/O/W) multiple emulsion for mucosal administration of ovalbumin (OVA) as a model candidate vaccine in BALB/c mice. Control and optimized OVA-containing W/O/W emulsion (OVA-Emul) and chitosan-modified W/O/W emulsion (OVA-Emul-Chi) formulations were administered intranasally and orally at an OVA dose of 100 μg. The mucosal and systemic immune responses were evaluated after the first and second immunization. The OVA-Emul formulations resulted in higher immunoglobulin-G (IgG) and immunoglobulin-A (IgA) responses as compared with aqueous solution. In addition, significant IgG and IgA responses were observed after the second immunization dose using the emulsions with both routes of administration. Intranasal vaccination was more effective in generating the systemic OVA-specific IgG response than the mucosal OVA-specific IgA response. Oral immunizations, on the other hand, showed a much higher systemic IgG and mucosal IgA responses as compared with the nasally treated groups. The results of this study show that squalane oil-containing W/O/W multiple emulsion formulations can significantly enhance the local and systemic immune responses, especially after oral administration, and may be adopted as a better alternative in mucosal delivery of prophylactic and therapeutic vaccines.

Effect of Cryoprotectant and Freeze-Drying Process on the Stability of W/O/W Emulsions

In order to protect a hydrophilic drug and to prolong its further delivery, the formulation of multiple emulsions could be worthy. However, the double emulsions are not stable, their structure can change, leading to the formation of a single emulsion as the destruction of the system, and the drug can release easily from the globules in liquid state. The freeze-drying technology could be used to produce dry emulsion, the powder form being much more stable. The aim of this work was to study the influence of a cryoprotectant and a freeze-drying process on the stability of W/O/W emulsions. Samples were frozen at two different freezing rate (ν f = 0.55°C/min and 1.25°C/min) and successively dried at two different sublimation temperature (T s = − 10°C and − 20°C). The particle size distributions were measured by granulometer and UV spectrophotometer was performed to investigate the leakage of internal constituent. The glass transition temperature (T g ) of the double emulsions was analyzed by DSC. The particle sizes became even smaller after freeze drying, except when κ-carrageenan is used as a cryoprotectant. In that case, the particles became aggregated after freeze drying, whatever the process conditions. The mean size is considerably reduced when the globules are diluted at low concentration in glucose and trehalose solution. When the concentration is increased, the size distribution is not significantly affected. The leakage of the internal aqueous phase to the external one during freeze drying was measured as an indicator of the structure stability. It is affected by the nature of the cryoprotectant and the conditions of the freeze-drying process. The leakage of the internal phase was smaller when cycle III (ν f = 1.25°C/min, T s = − 10°C) was processed. From our experiments, we suppose that the water transfer from the inner phase to the outer aqueous phase results in the diminution of the globules size in double emulsion. The T g of the double emulsions diluted with trehalose and glucose were determined at − 33.8°C and − 47.1°C. In contrast, the T g of double emulsion with κ-carrageenan and HES did not appear.

Evaluation of in vitro release and skin irritation of benzoyl peroxide-containing products

Benzoyl peroxide (BPO) has been known as a highly effective topical agent in acne vulgaris therapy for a long time. It induces an irritant dermatitis with erythema and scaling. Therefore, the aim of this study was to formulate BPO containing w/o/w multiple emulsion and gel formulations with and without chitosan microparticles to decrease skin irritation and to compare the release profiles through cellulose acetate, cellophane membranes and excised rat skin. A commercial preparation was also used and the similarities between commercial and experimental formulations were assessed by difference factor (f). The release results indicated that gel base exhibited a higher drug release than the other experimental formulations (p<0.05). The release rate of BPO from different membranes was found to be statistically different (p<0.05). Histological examinations realized by light microscopy on wistar rat skin indicated no observable damage to whole experimental formulations. The results described in this study pointed out that w/o/w multiple emulsion system containing chitosan microparticles has shown the lowest release rate and could be suggested as an effective carrier for BPO to achieve sustained release, to prevent skin irritation and to protect the drug from environmental factors. Moreover, this system could present additional therapeutic benefits due to the wound healing effects of chitosan.

Properties of various thermoassociating polymers: pharmaceutical and cosmetic applications

This paper describes the main results obtained in our group on three thermoassociating polymers with interesting applications in the pharmaceutical and cosmetic fields. These three polymers are based on the poloxamer structure. The poloxamer macromolecules per se have interesting thermoassociating properties in aqueous solutions but they can also be integrated as sub-units in the design of more complex molecular architectures such as grafted poloxamers. The thermoassociating properties and the sol–gel transition of these three different systems were investigated in aqueous solutions mainly by rheology. The poloxamer gels were then assessed as in situ generated implants for the controlled release of vancomycin. They were also incorporated in more complex formulations containing liposomes to protect unstable actives such as antisense oligonucleotides. As regards the grafted poloxamers, a lower polymer concentration was required to induce the gelation. Moreover, the viscosity of these hydrogels remains high enough under shear rates that correspond to a topical application. These properties make them suitable for the formulation of multiple emulsions that can release an entrapped active molecule under shear when the formulation is topically applied.

Preparation and Evaluation of Multiple Emulsions Water-in-oil-in-water (w/o/w) as Delivery System for Influenza Virus Antigens

In this study, investigations have been carried out to prepare adjuvant active delivery systems; multiple water-in-oil-in-water (w/o/w) emulsion formulations, containing influenza virus surface antigen Hemagglutinin (HA). A modified two-stage emulsification method has been used to prepare multiple emulsions. After improving multiple (w/o/w) emulsion formulations; F1: purified antigen solution (PAS)/soybean oil, HCO-40 and span 80/pluronic F-68, F2: PAS and HPβCD/soybean oil, HCO-40 and span 80/pluronic F-68, F3: PAS/squalane, HCO-40 and span 80/pluronic F-68, formulations were selected for the stability study that continued for a 3 month duration. To evaluate the stability of these formulations, microscopic observation, osmolarities of the internal and external aqueous phases, pH, globule size and viscosity were determined. SDS-PAGE (silver staining) was used to evaluate HA and the micro-bicinchoninic acid (mBCA) assay was used to determine the in vitro release of antigen from formulations. Immune responses of formulations were investigated in Wistar Albino rats and compared with the immune response raised against the conventional vaccine. These responses were detected with Hemagglutination Inhibition (HAI) assay.The results of this study demonstrated that HA was well entrapped in the multiple (w/o/w) emulsion formulations. Molecular weight and antigenicity of the entrapped HA were not affected by the emulsification procedure. These results suggest that multiple emulsion formulations entrapping influenza antigen may have potential for immunization studies as one of the vaccine delivery system with adjuvant properties.

Formulation of shear rate sensitive multiple emulsions

This work mainly concentrates on the formulation of W/O/W multiple emulsions capable of breaking and releasing their inner aqueous phase under shear rates compatible with agroalimentary, pharmaceutical and cosmetic applications. Three kinds of multiple emulsions were studied: one with a high concentration of primary emulsion, not viscosified in the external aqueous phase; multiple emulsions gelified with a synthetic polymer (Carbopol 974P ®); and other multiple emulsions thickened with chemically modified cellulose (hydroxypropylcellulose). The results of this study show the influence of the composition of the external aqueous phase of the emulsions on their fragmentation and release as a function of the shear rate. Despite these differences of behavior with respect to the shear rate, each emulsion fits to Taylor’s theoretical framework, indicating that the bursting mechanisms of the globules under shear are the same whatever the composition of the multiple emulsions.

マルチプルエマルションの調製と特徴

マルチプルエマルションの調製と特徴