Microemulsion Formulation Research Articles

Development and cytotoxicity evaluation of multiple nanoemulsions for oral co-delivery of 5-fluorouracil and short chain triglycerides for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world, but current chemotherapy options are limited due to adverse effects and low oral bioavailability of drugs. In this study, we investigated the obtainment parameters and composition of new multiple nanoemulsions (MN) based on microemulsions for oral co-delivery of 5-fluorouracil (5FU) and short-chain triglycerides (SCT, either tributyrin or tripropionin). The area of microemulsion formation was increased from 14% to 38% when monocaprylin was mixed with tricaprylin as oil phase. Addition of SCT reduced this value to 24–26%. Using sodium alginate aqueous dispersion as internal aqueous phase (to avoid phase inversion) did not further affected the area but increased microemulsion viscosity by 1.5-fold. To obtain the MN, selected microemulsions were diluted in an external aqueous phase; droplet size was 500 nm and stability improved using polyoxyethylene oleyl ether at 1–2.5% as surfactant in the external phase and a dilution ratio of 1:1 (v/v). 5FU in vitro release could be better described by the Korsmeyer-Peppas model. No pronounced changes in droplet size were observed when selected MNs were incubated in buffers mimicking gastrointestinal fluids. The 5FU cytotoxicity in monolayer cell lines presenting various mutations was influenced by its incorporation in the nanocarrier, presence of SCT and cell mutation status. The MNs selected reduced the viability of tumor spheroids (employed as 3D tumor models) by 2.2-fold compared to 5FU solution and did not affect the survival of the G. mellonella, suggesting effectiveness and safety.

Acacetin-loaded microemulsion for transdermal delivery: preparation, optimization and evaluation

Context Acacetin is reported as a potential drug candidate for the treatment of atrial fibrillation. However, clinical applications are limited by poor water solubility, limited ethanol solubility, and extremely low oral bioavailability. Objective The present study prepared and evaluated acacetin-loaded microemulsion (ME) to achieve efficient pharmacokinetics together with no or minimal invasiveness for transdermal delivery. Materials and methods The formulation of ME was determined by the water titration method based on solubility results. The optimized formulation was achieved by the simplex lattice experiment design. The optimized ME formulations FA, FB and FC (FA with 10% and 50% DMSO as enhancers, respectively) were evaluated by ex vivo permeation with Franz diffusion cell and excised mice skin. In vivo pharmacokinetic studies were also performed at 8 mg/kg in rats within 6 h by transdermal administration. Results The optimal ME (FA) was comprised of 12.2% caprylic acid decanoate monoditriglyceride (MCF-NF), 39.8% Smix (RH40: Trans = 2:1 w/w) and 48% water, respectively. Acacetin-loaded FA with particle size 36.0 ± 3.6 nm and drug solubility 803.7 ± 32.1 mg/g was prepared. FB had significantly higher cumulative amounts and higher AUC0-∞ (196.6 ± 11.0 min × μg/mL, p < 0.05) than that FA alone (121.4 ± 33.1 min × μg/mL). Discussion and conclusions The formulation of ME combined with the penetration enhancer can effectively improve the solubility and percutaneous absorption efficiency of acacetin, providing a new option for the non-invasive delivery of acacetin.

Theoretical studies on the quercetin interactions in the oil-in-water F127 microemulsion: A DFT and MD investigation

Quercetin (Q) has attracted the attention of researchers for potential applications in advanced therapeutic treatments due to its antioxidant attributes and renal tissue improvement. F127-based oil-in-water microemulsions improved the bioavailability of Q and showed greater retention and more stable release. In this study, Q-loaded microemulsion was designed with the help of simulation techniques. The mechanism of action of Q was investigated in the bulk and microemulsion forms. The simulation results show the fast accumulation of Q molecules around 2,2-diphenyl-1-picrylhydrazyl (DPPH) molecules (free radicals) in bulk form and the slow accumulation of Q molecules around DPPH in microemulsion form. The stable release of Q in microemulsion form was found to be due to the powerful van der Waals (vdW) interactions between Q and F127. For a better and deeper understanding of the nature of mutual interactions between Q (enol and keto forms) and F127, quantum mechanical calculations were performed at the B3LYP/6-31G(d,p) level of theory. In particular, atoms in molecules (AIM) and natural bond orbital (NBO) analyses were performed to evaluate the strength of the interactions between Q and F127. The results showed that the formation of a strong hydrogen bond (HB) between Qenol and F127 stabilizes the microemulsion system and can contribute to the better performance of Q microemulsion compared to free Q in bulk.

Improvement in Skin Penetration Capacity of Linalool by Using Microemulsion as a Delivery Carrier: Formulation Optimization and In Vitro Evaluation.

Linalool is an aromatic oil with analgesic, anti-inflammatory and anti-UVB-induced skin damage effects. The aim of this study was to develop a linalool-loaded microemulsion formulation for topical application. In order to quickly obtain an optimal drug-loaded formulation, statistical tools of the response surface methodology and a mixed experimental design with four independent variables of oil (X1), mixed surfactant (X2), cosurfactant (X3) and water (X4) were used to design a series of model formulations in order to analyze the effect of the composition on the characteristics and permeation capacity of linalool-loaded microemulsion formulations and to obtain an appropriate drug-loaded formulation. The results showed that the droplet size, viscosity and penetration capacity of linalool-loaded formulations were significantly affected by formulation component proportions. The skin deposition amount of the drug and flux of such formulations expressively increased about 6.1-fold and 6.5-fold, respectively, when compared to the control group (5% linalool dissolved in ethanol). After 3 months of storage, the physicochemical characteristics and drug level did not show a significant change. The linalool formulation-treated rat skin showed non-significant irritation compared to skin treatments in the distilled-water-treated group. The results showed that specific microemulsion applications might be considered as potential drug delivery carriers for essential oil topical application.

KETOCONAZOLE LADEN MICROEMULSION BASED GEL FORMULATION AGAINST SKIN FUNGAL INFECTION

Objective: The present research was aimed to develop ketoconazole (KT) loaded microemulsion-based gel formulation for effective topical delivery through enhanced drug solubility, improved skin permeation and reduced side effects overcoming drawbacks of conventional dosage forms. Methods: For the selection of oil, surfactant and co-surfactant mixture (Smix) ratio, the phase titration method was used and pseudo-ternary phase diagrams were prepared. D-optimal mixture design was employed to optimize the microemulsion system taking oil, Smix and water as independent variables and particle size, polydispersity index, zeta potential, % transmittance and cumulative % drug release as response variables. Finally, topical gel formulation of KT-loaded microemulsion was developed and evaluated for physico-chemical properties, rheological properties, in vitro drug release kinetics and ex-vivo drug permeation. Results: The optimized microemulsion was found to be a transparent formulation with 19.7 nm particle size, 0.268 polydispersity index,-0.2 mV zeta potential, 97.83% transmittance and 85.85% cumulative drug release at 24 h. The developed gel of optimized microemulsion possessed pH 6.20, viscosity 2178 cps, spreadability 18.634 g.cm2/sec, adhesiveness 45.989 N/mm2, and cohesiveness-85.583. The in vitro drug release was found to be 69.08 % (at 24 h), showing sustained release and Higuchi kinetic profile. The developed gel exhibited 1.84-fold higher drug permeation flux as compared to the marketed product. Conclusion: The developed gel formulation possessed all desired quality attributes and physico-chemical properties. The in vitro and ex-vivo study data proved it’s suitability as a better alternative to conventional products in the effective treatment of fungal skin infections.

Study progress on moringa seed oil with microemulsion: bibliometrics analysis of year 2012-2023

Transdermal drug delivery systems increase the effectiveness of a drug substance, and one of them is a microemulsion. Moringa oil has anti-inflammatory, antioxidant, and antibacterial activity. The purpose of this study is to conduct a bibliometric analysis research on moringa oil formulated as microemulsions. A total of 5 English articles from the Scopus databases from 2012 to 2023 US sources were used in the bibliometrics analysis of Moringa oleifera seeds oil related to microemulsions. The bibliometrics analysis shows research trends, including the most used keywords depicted in visualizations using the VOSViewer application, article publishers, affiliations, and the author's country of origin. The most used keywords are microemulsions, microemulsion, Moringa oleifera, antioxidant activities, and antioxidants. The most publishers are Key Engineering Materials, the most affiliated are Chiang Mai University and Thamasat University, and most authors are from Thailand. The study of microemulsion formulations of Moringa seed oil has yet to be widely carried out but has been cited by other researchers.

Preparation cypermethrin microemulsion formulation and evaluation its insecticidal activity on Aphis gossypii(Hemiptera: Aphididae) in green space of Ahvaz

Preparation cypermethrin microemulsion formulation and evaluation its insecticidal activity on Aphis gossypii(Hemiptera: Aphididae) in green space of Ahvaz

The formation and stability of microemulsions formed with organic solvent as inner/outer phases: Insight from DPD simulation

Organic solvents are selected as the inner/outer phases to construct the microemulsion systems can open new areas of application in providing a reaction medium for various organic conversions. O/W and reverse W/O microemulsions are prepared, using four different organic solvents of Benzene, Cyclohexane, Octane and Dodecane and nonionic surfactant Dodecylhexaglycol (C12E6) as a stabilizer by using Dissipative particle dynamics (DPD) simulation method. The oil–water ratio is applied to control the topology of the microemulsions and more importantly achieve the transformation of O/W and reverse W/O microemulsions. For cyclic hydrocarbons, Cyclohexane needs the same ratio to form O/W microemulsions and reverse W/O microemulsions with Benzene though possessing the special π chemical bond. However, the liner hydrocarbon with a short molecular chain of Octane is conducive to form O/W microemulsions and the longer chain of Dodecane is easier to create reverse W/O microemulsions. The interfacial tension and end-to-end distance values are lowest when O/W and reverse W/O microemulsions are formed in the system. The temperature-induced stability results show that O/W microemulsions have the same stability for four organic solvents, but Cyclohexane and Octane present superior strength than Benzene and Dodecane for reverse W/O microemulsions. In addition, the more substantial hydrophobic effect of Cyclohexane and Dodecane promotes better salt-induced stability for O/W microemulsions, interestingly, reverse W/O microemulsions present the same stability for four systems. Our findings are instructive in providing the physical understanding necessary for future progress in research and applications of microemulsions, especially for organic solvents as the oil phase in the field of microreactors.

Formulation and Evaluation of Tea tree/ Rosemary Essential oil-based Microemulsion for Antimicrobial Activity

ABSTRACT: This research aims to prepare microemulsion from Tea Tree and Rosemary essential oil to treat gram-positive and gram-negative bacterial infections. A phase titration has been used to make the proposed microemulsion, which contained 71% water, 23% of a 1:1 mixture of propylene glycol (surfactant), tween 80 (co-surfactant), and 6% of tea tree/rosemary essential oil. In Rosemary essential oil pale yellowish transparent microemulsion, droplet size, zeta potential, and polydispersity index (PDI) of 58.9, 883.6, and 0.678, respectively, showed a stable microemulsion. Tea tree oil loaded in a light, clear microemulsion with zeta potential, droplet size, and polydispersity index (PDI) values of 265.9, 746.8, and 0.987, respectively, indicated a stable microemulsion. The RMO/TTO micro emulsion's viscosity was 1.844/1.933 cps, and its pH ranged from 4.69 to 5.59. The formulation was determined to be a safe, reliable, and effective one in light and good in stability experiments. Escherichia coli, Staphylococcus aureus, and Candida albicans can all be treated using a microemulsion that contains 6% tea tree oil and rosemary oil by agar well diffusion method. Both the EOs-based microemulsion showed more zone of inhibition against Escherichia coli and Candida albicans while Staphylococcus aureus is the less susceptible zone of inhibition. The microemulsion formulation's minimum inhibitory concentration was effective against Staphylococcus aureus, Candida albicans, and E. coli on all physiological parameters. It can be concluded that TTO/RMO essential oil-loaded microemulsion is considered a promising substitute for the current gram-positive and gram-negative regimens.

Phase stability, fuel properties, and diesel engine performance of palm‐oil‐based microemulsion biofuels

AbstractMicroemulsification and blending are two viscosity‐modifying techniques of vegetable oils for direct use with diesel engine. In this study, alcohol blends are mixtures of ethanol, diesel, and palm‐oil biodiesel while microemulsion biofuels are thermodynamically stable, clear, and single‐phase mixtures of diesel, palm oil, and ethanol stabilized by surfactants and cosurfactants. Although there are many studies on biofuels lately, there is limited research on using biodiesel as a surfactant in microemulsion formulations and applied on engine performance at different engine loads. Therefore, the objectives are to investigate phase stability and fuel properties of formulated biofuels (various blends and microemulsions), to determine the engine performance at different engine loads (no load, and from 0.5 to 2.0 kW), and to estimate laboratory‐scale cost of the selected biofuels compared to diesel and biodiesel. The results showed that phase stability and fuel properties of selected microemulsion biofuels are comparable to diesel and biodiesel. These microemulsion biofuels can be applied to the diesel engine at different loads while diesel‐ethanol blends and palm‐oil‐biodiesel‐ethanol blends cannot be. It was found that the energy efficiencies of the system using microemulsion biofuels were slightly lower than the average energy efficiency of diesel engine. From this study, it can be summarized that microemulsion biofuels can be formulated using palm‐oil biodiesel (palm‐oil methyl ester) as a bio‐based surfactant and they can be considered as environmentally‐friendly alternatives to diesel and biodiesel. However, cost considerations showed that the raw materials should be locally available to reduce additional costs of microemulsion biofuels.

Development and characterization of clove oil microemulsion

Clove oil is one type of essential oil from clove flower buds (Syzygium aromaticum) which contains eugenol compounds. Clove oil is volatile in nature and highly affected by heat, thus incorporating it in a microemulsion system can increase its shelf life of the oils. This study aimed to formulate and characterize microemulsion preparations with clove flower essential oil. The microemulsion existence region was determined by constructing a pseudo-ternary phase diagrams and prepared with four components, i.e. isopropyl myristate, tween-80 as a surfactant, polyethylene glycol 400 (PEG 400) as a co-surfactant, and water as the aqueous phase. The optimized clove oil microemulsion formulation was subjected to an evaluation of various parameters, such as organoleptic properties, %transmittance, pH, viscosity, stability, particle size, zeta potential, and polydispersity index (IP). Based on the results of the study, the highest compound component in clove oil was eugenol with a % area of ​​63.79%. The results revealed that the construction of a phase diagram and the use of the phase titration method constituted a suitable technique for the preparation of microemulsions as most of the formulations were transparent. It was found that the tween-80:PEG 400 ratio of 2:1 with an oil:S-mix ratio of 1:9 generated an optimum results. The clove oil microemulsion had a globule size of 17.69±0.025nm, a polydispersity index value of 0.057±0.0043, zeta potential of-5.36±0.23mV, and a pH value of 7.3±0.1, a viscosity value of 466.7±9.06., and %transmittance of 99.9±0.1. According to these findings, the microemulsion formulation might serve as a suitable drug delivery system.

Topical Delivery of Diacetyl Boldine in a Microemulsion Formulation for Chemoprotection against Melanoma.

This study aimed to develop a microemulsion formulation for topical delivery of Diacetyl Boldine (DAB) and to evaluate its cytotoxicity against melanoma cell line (B16BL6) in vitro. Using a pseudo-ternary phase diagram, the optimal microemulsion formulation region was identified, and its particle size, viscosity, pH, and in vitro release characteristics were determined. Permeation studies were performed on excised human skin using Franz diffusion cell assembly. The cytotoxicity of the formulations on B16BL6 melanoma cell lines was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. Two formulation compositions were selected based on the higher microemulsion area of the pseudo-ternary phase diagrams. The formulations showed a mean globule size of around 50 nm and a polydispersity index of <0.2. The ex vivo skin permeation study demonstrated that the microemulsion formulation exhibited significantly higher skin retention levels than the DAB solution in MCT oil (Control, DAB-MCT). Furthermore, the formulations showed substantially higher cytotoxicity toward B16BL6 cell lines than the control formulation (p < 0.001). The half-maximal inhibitory concentrations (IC50) of F1, F2, and DAB-MCT formulations against B16BL6 cells were calculated to be 1 µg/mL, 10 µg/mL, and 50 µg/mL, respectively. By comparison, the IC50 of F1 was 50-fold lower than that of the DAB-MCT formulation. The results of the present study suggest that microemulsion could be a promising formulation for the topical administration of DAB.

FORMULATION OF NANOSTRUCTURED LIPID CARRIERS OF HALOPERIDOL PREPARED BY USING CLARIFIED BUTTER

Objective: To develop the nanostructured lipid carriers (NLC’s) using clarified butter. Methods: Haloperidol-loaded microemulsion templates were prepared by using Smix of Tween 80 and propylene glycol in the ratio 1:2. The selection of the mixture of surfactant and co-surfactant (Smix) and their appropriate proportion were decided by the traditional way of construction of pseudo ternary phase diagrams. 22 factorial design was used to check the amenability of the formulation for its successful scale-up. Sonication time and the amount of Smix were selected as independent variables and their influence on the globular size (Y1) of the microemulsions formed was evaluated by using statistical models. Composition of the optimized microemulsion template was further used to prepare haloperidol-loaded NLC’s by ‘microemulsion quenching method’. Results: The microemulsion formulations containing Tween 80 as a surfactant and propylene glycol as a co-surfactant exhibited the smallest globular size and hence this composition was used further to implement factorial design as design of experiments. The statistical analysis of the data suggested that the microemulsion formulation can be scaled up successfully. NLC’s were prepared from the optimized microemulsion formulation as template. The globular size of NLC’s was confirmed by Transmission Electron Microscopy and was observed to be in the range of 300 to 600 nm. Conclusion: The present work suggested that the latency of the clarified butter as a natural blend of solid lipid and liquid lipids can be successfully explored to prepare nanostructured lipid carriers.

Design and Assessment of a Microemulsion-Based Transdermal Drug Delivery System for Meloxicam; Examination of Formulation Ingredients

Background: The goal of creating meloxicam-loaded microemulsion formulations was to increase meloxicam permeability through the skin. Using pseudo-ternary phase diagram construction and full factorial design, eight formulations with three independent variables (water percent, oil percent, and surfactant/co-surfactant percent) were selected to be prepared. &#x0D; Methods: This research evaluated the formulation's characteristics, including particle size, viscosity, and release profile. FT-IR and DSC techniques were also utilized to investigate the effect of microemulsion components on rat abdomen skin, and the permeability of meloxicam-loaded microemulsions via rat abdomen skin was also evaluated by calculating permeability parameters such as Jss, Dapp, Tlag, ERflux, ERD, and ERP. &#x0D; Results: When compared to a saturated aqueous solution of meloxicam as a reference, the findings showed that all microemulsion (ME) formulations considerably increased meloxicam permeability through rat skin. Water percent had a direct and significant relationship with Jss, and oil percent had a direct and significant relationship with Dapp, according to analysis regression. &#x0D; Conclusion: ME components also caused alterations in the skin's lipoprotein bilayers, which might enhance formulation permeability through the skin.

Formulation and Evaluation of Phyto-phospholipid complex of Methanolic Extract of leaves of Andrographis paniculate

Andrographis paniculata is widely used plant in Southeast Asia, China and India as a healthy food, it contains andrographolide as a pharmacologically active constituent isolated from leaves and roots of Andrographis paniculata and has got wide therapeutic potential including anti-inflammatory, antiviral and hepatoprotective activity but its bioavailability is limited due to its poor solubility, rapid clearance rate and high plasma protein binding. Several attempts involving formulation of liposomes, noisome, nanoparticles, micro emulsions and solid lipid nanoparticle have been done to perk up its solubility and hence bioavailability. The aim of the proposed work is to formulate Phytosomes of methanolic extract of leaves of Andrographis paniculate. The Phytosomes were formulated using thin film hydration technique with varying molar ratios of phospholipid and extract of leaves of Andrographis paniculate. Formulated Phytosomes were characterized for particle size and size distribution, entrapment efficiency, in-vitro drug release characteristics, scanning electron microscopy and FTIR analysis.

Microemulsion-based lutein extraction from marigold petals: Process optimization and stabilization evaluation

In present study, a novel, efficient and environmental friendly microemulsion extraction method was established to extract lutein from marigold petals powder (MPP). The optimum microemulsion formulation was obtained by combining the screening of oils, co-surfactants and ternary phase diagram. Based on the saturation solubility of lutein, isoamyl acetate and n-propanol were selected as oil phase and co-surfactant, respectively. A 5 mL microemulsion consisting of Tween80/n-propanol/isoamyl acetate/water (36:36:18:10 wt%) was used for the extraction of lutein from 20 mg MPP, with the highest extraction efficiency of 95.17%. For lutein microemulsion, the average droplet size was 26.44 ± 0.17 nm, the polydispersity index was 0.37 ± 0.00 and Zeta potential was − 11.20 ± 0.26 mV. Compared with ethanol extract (EE), MPP microemulsion extract (LME) had higher stability under different temperature, pH, and storage time conditions. This study would provide a new alternative method for lutein extraction, and also could be expected to be applied for other poorly water-soluble ingredients.

Influencing of hydrogeochemical conditions and engineering parameters on phase behaviors and remediation performance of in-situ microemulsion for residual PCE in aquifers

In-situ microemulsion has great potential for remediation of chlorinated solvent contaminated aquifers due to its efficient solubilization, and the in-situ formation and phase behaviors of microemulsion is a key factor in determining the remediation performance. However, the role of aquifer properties and engineering parameters on microemulsion in-situ formation and phase transition has been rarely attended. In this work, the influences of hydrogeochemical conditions on in-situ microemulsion phase transition and solubilization ability for tetrachloroethylene (PCE) were explored, and the formation condition, phase transition and removal efficiency for in-situ microemulsion flushing under various flushing conditions were investigated. The results indicated that the cations (Na+, K+, Ca2+) all facilitated the microemulsion phase altering from Winsor I → III → II, whereas the anions (Cl−, SO42−, CO32−) and pH variation (5–9) had no profound influence on phase transition. Besides, the solubilization capacity of microemulsion was enhanced by the pH variation and the cations, which was proportional to the cation concentration of groundwater. The column experiments demonstrated that PCE underwent the phase transition from emulsion to microemulsion and then to micellar solution during the flushing process. The formation and phase transition of microemulsion were mainly related to injection velocity and PCE residual saturation in aquifers. The slower injection velocity and higher residual saturation were profitable to the in-situ formation of microemulsion. In addition, the removal efficiency could achieve 99.29 % for residual PCE at 12 °C, enhancing with the finer porous medium, lower injection velocity and intermittent injection. Furthermore, the flushing system exhibited high biodegradability and weak reagent adsorption onto the aquifer media, presenting a low environmental risk. This study provides valuable information on the in-situ microemulsion phase behaviors and the optimal reagent parameters, facilitating the application of in-situ microemulsion flushing.

In-Situ Visualization of Imbibition Process Using a Fracture-Matrix Micromodel: Effect of Surfactant Formulations toward Nanoemulsion and Microemulsion

Summary Spontaneous imbibition can help to improve the oil recovery of unconventional reservoirs owing to the significant capillarity. Although the dependence of imbibition dynamics of surfactants on wettability and interfacial tension (IFT) is understood, the mechanisms of nanoemulsion and microemulsion forming surfactants for higher imbibition recovery are not as clear. Herein, we conducted a series of imbibition experiments on a visual fracture-matrix micromodel, aiming to directly observe the imbibition processes of these surfactant formulations. Four surfactant-based fluids, including a common surfactant [fatty alcohol polyoxyethylene ether, sodium sulfate (AES)], a surfactant composition of nanoemulsion (nE-S), an ex-situ nanoemulsion (nE), and a situ microemulsion forming surfactant (mE-FS), were designed and used in this work for comparison with brine. The results suggested that AES, nE-S, nE, and mE-FS could substantially stimulate the imbibition invasion, and mE-FS generated the greatest imbibition depth and sweeping area followed by nE. The imbibition dynamics were governed by the interfacial interactions among oil, aqueous phase, and solid surface, leading to different imbibition patterns for these five fluids. AES and nE-S could reduce the oil-aqueous IFT to 10−1 mN/m and alter the wettability to a weak water-wet state as a result of surfactant adsorption, leading to a slightly higher imbibition invasion compared with brine. AES imbibition produced large oil droplets mainly because of the snap-off effect at the nozzle to the fracture, whereas nE-S produced smaller oil droplets due to the weak in-situ emulsification. nE as a formed nanoemulsion with an internal oil phase demonstrated a lower IFT of 10−2 mN/m and superior capacity in changing surface wettability mainly through the adsorption and spreading of nanosized oil droplets on the surface. The oil phase was heavily emulsified forming dense droplets on the oil-aqueous interface. mE-FS readily formed Winsor Type III microemulsion and produced an IFT of 10−3 mN/m magnitude. The wettability was changed mainly because of the peeling oil film and formation of microemulsion on the surface induced by solubilization. The dynamic increase of the oil-aqueous IFT at the imbibition front caused by the adsorption loss of surfactant to the surface and partitioning to the oil phase promoted capillary-driven imbibition for nE and mE-FS. We modified an imbibition model to incorporate the solubilization effect, leading to a much better fitting with the experimental data.

Composites of Montmorillonite and Titania Nanoparticles Prepared by Inverse Microemulsion Method: Physico-Chemical Characterization.

TiO2/montmorillonite composites were synthesized using inverse micellar route for the preparation of titania nanoparticles (4-6 nm diameter) in 1-hexanol and for the dispersion of one of the clay components. Two series of composites were obtained: one derived from cetyltrimethylammonium organomontmorillonite (CTA-Mt), exfoliated in 1-hexanol, and the other from sodium form of montmorillonite (Na-Mt) dispersed by formation of an inverse microemulsion in 1-hexanol. The TiO2 content ranged from 16 to 64 wt.%. The composites were characterized with X-ray diffraction, scanning/transmission electron microscopy/energy dispersive X-ray spectroscopy, thermal analysis, and N2 adsorption-desorption isotherms. The Na-Mt-derived component was shown to undergo transformation to CTA-Mt, as indicated by basal spacing of 17.5 nm, due to the interaction with the CTABr surfactant in inverse microemulsion. It was also better dispersed and intermixed with TiO2 nanoparticles. As a result, the TiO2/Na-Mt series displayed superior textural properties, with specific surface area up to 256 m2g-1 and pore volume up to 0.247 cm3g-1 compared with 208 m2g-1 and 0.231 cm3g-1, respectively, for the TiO2/CTA-Mt counterpart. Members of both series were uniformly mesoporous, with the dominant pore size around 5 nm, i.e., comparable with the dimensions of titania nanoparticles. The advantage of the adopted synthesis method is discussed in the context of other preparative procedures used for manufacturing of titania-clay composites.

Transdermal delivery of acemetacin loaded microemulsions: preparation, characterization, in vitro – ex vivo evaluation and in vivo analgesic and anti-inflammatory efficacy

The goal of this study was to see if microemulsions might be used as a transdermal drug delivery system for acemetacin (ACM). Microemulsions containing isopropyl myristate, Tween 80, Transcutol HP, Labrafil M1944 CS, ethanol, and distilled water were used to create pseudo-ternary phase diagrams. In microemulsion systems, the ultimate concentration of ACM was 1% (w/w). Conductivity, droplet size, zeta potential, polydispersity index, viscosity, and pH were used to characterize the microemulsions. Furthermore, in vitro permeability investigations were carried out utilizing diffusion cells derived from the dorsal skin of mice. The results of characterization studies such as droplet size, polydispersity index, zeta potential, conductivity values of ideal formulation were found 9.107 ± 1.588 nm, 0.283 ± 0.062, −0.313 ± 0.006 mV, 0.018 ± 0.012 µS/cm, respectively. The penetration of ACM from ideal formulation was greater than the other developed formulations. The anti-inflammatory effect of ACM was evaluated in mice using the paw edema test. In addition, all test microemulsions had a significant analgesic effect in the hot plate and tail-flick tests as compared to the control. Finally, microemulsion formulations might be used to deliver ACM transdermally.