Preparation, optimization and characterization of microemulsions 167 5. Microemulsion, bicontinous, cosurfactants, lipophilic drugs, thermodynamic stability. Mar 18, 2012 microemulsion microemulsions are thermodynamically stable dispersions of oil and water stabilized by a surfactant and, in many cases, also a cosurfactant. To investigate the effect of various surfactants and cosurfactants, and their ratio on microemulsions prepared with isopropyl palmitate ipp methods. The winsor 1 system refers to an ow microemulsion coexisting with an excess oil phase. Evidences of intranasal drug delivery systems formulated using mucoadhesive agents and their benefits in enhancing nosetobrain drug transport have been. Winsor iv systems 1, or microemulsions 2, are macroscopically monophasic fluid transparent compounds made up by mixing water and hydrocarbon in the presence of suitable surface active agents. Acid hydrolysis of bromazepam catalyzed by micelles, reverse. The interfacial properties interfacial thicknesstensionrigidity of these linker based microemulsions were also studied. Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water, surfactant, and cosurfactant.
Detergentless microemulsions as media for enzymatic. The phase behavior and properties of solutions containing amphiphiles, organic liquids, and water. Bicontinuous structure zones in microemulsions nature. Enhancing solubilization in microemulsionsstate of the.
These are a special kind of colloidal dispersion that have attracted a great deal of attention because of their ability to solubilise otherwise insoluble materials. Pdf enhancing solubilization in microemulsionsstate of the. Formulations, solvency and physical properties bourrel, maurice, schechter, robert on. Effect of microemulsion variables on copper oxide nanoparticle uptake by aot microemulsions nashaat n. Durham etheses control of crystallisation through the use of. Coalescence and solubilization kinetics in linkermodified. Microemulsions and related systems bourrel maurice. Polymerinduced structural transitions in microemulsions.
Single phase microemulsions and in situ microemulsions for. This work aimed to enhance the distribution of a solid essential oil compound, thymol, using oilinwater ow microemulsions for its solubilization. University of cologne low surfactant content, low energy input. Micellization, solubilization, and microemulsions, vol. Pharmaceutical applications of microemulsions increase bioavailability of drugs poorly soluble in water. In order to examine the effect of alkyl chain length of ag on the solubilization capacity of water by ag, we have measured the limiting amount of solubilized water by reverse micelles of ag having a different alkyl chain length at 25. In chapter 1 a short introduction about the background, various aspects and applications. Water solubilization in microemulsions containing amines. The pseudoternary phase diagrams were constructed to determine the composition of microemulsions. Acid hydrolysis of bromazepam catalyzed by micelles. On the other hand, wo microemulsions were determined at the corner of surfactantrich region along dilution. October 3, 1992 we predict, qualitatively, the structural transitions in microemulsion systems induced by nonionic. Solubilization in microemulsions and application to separations.
Solubilization and thermal properties of microemulsions. The effective use of microemulsions has increased dramatically during the past few decades as major industrial applications have expanded in a variety of fields. Microemulsions have been investigated by many scientists interested in liquid state and surface physicochemistry and by many technologists foreseeing numerous applications in industry8,9. Micellization, solubilization and microemulsions springerlink.
Winsors fundamental hypothesis on a natural interfacial curvature depending on the values of the formulation variables, this unique book shows scientists how to understand the intrinsic structure of these complex systems and their corresponding physical properties. Micro emulsion are having wide applications in colloidal drug delivery systems for the purpose of. Drug delivery through microemulsions is a promising area for continued research with the aim of achieving controlled release with enhanced bioavailability and for drug targeting to various. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Qutubuddin chemical engineering department, case institute of technology, case western reserve university, cleveland, oh44106 u. The microemulsions lower value of have been found to bring about an increase in the reaction rate where high 1butanol content dominates ctab1butanol reverse micelles whereas, in microemulsions higher value of, the rate constant is higher as compared to aqueous solution and the corresponding micelles but lower than that in microemulsions. Formation of cyclodextrinstabilized nanoemulsions and. Department of chemical and petroleum engineering, university of calgary, calgary, ab, t2n 1n4, canada received 20 april 2007.
They were used to solubilize drugs and to improve topical drug availability. Overall, the ow microemulsions were found to form at a small region of the ternary phase diagrams with a relatively large ratio of water, compared to wo nanoemulsion, along dilution lines 1 and 2. Enhancing solubilization in microemulsionsstate of the art. Enhanced oil solubilization using microemulsions with linkers. Oil and water are immiscible and they separate into two phases when mixed, each saturated with traces of the other component capek, 1999. Microemulsions this chapter is devoted to another important property of surfactants, that of stabilization of wateroil films and formation of microemulsions. Dec 15, 2008 the effective use of microemulsions has increased dramatically during the past few decades as major industrial applications have expanded in a variety of fields. Development and evaluation of a microemulsion formulation. Personal care products pesticide formulations cutting oils. In microemulsions, hydrophilic drugs are incorporated by solubilization in the aqueous phase, whereas lipophilic drugs are solubilized in oil or oilsurfactant mixtures. Supersolubilization in chlorinated hydrocarbon microemulsions. Percolative conduction in microemulsion type systems nature.
They are dispersed, macroscopically homogeneous, thermodynamically stable, and optically transparent dantas neto et al. Notably, the micellar solubilization was known earlier to formulation scientists and work well in small molecular drugs, while microemulsion. Microemulsions, by virtue of their lipophilic nature and low globule size, are widely explored as a delivery system to enhance uptake across mucosa hu et al. Nonionic microemulsions as solubilizers of hydrophobic drugs. A potential novel drug delivery system jaspreet kaur saini 1, ujjwal nautiyal 1, senthil kumar m 1, devendra singh 2, firoz anwar 3 1department of pharmaceutics, himachal institute of pharmacy, paonta sahib, himachal pradesh, india. Lipophilic linker optimization article pdf available in journal of surfactants and detergents. Microemulsions are thermodynamically stable dispersions of oil and water stabilized by a surfactant and, in many cases, also a cosurfactant. Enter your mobile number or email address below and well send you a link to download the free kindle app. The aim of this investigation was to design and develop a microemulsion formulation of clopidogrel for enhancing its solubility, and hence its oral bioavailability. Download micellization, solubilization, and microemulsions, vol.
Development and evaluation of a microemulsion formulation for. Durham etheses control of crystallisation through the use. The water solubilization capacity of sodium bis2ethylhexylsulfosuccinate aot in isooctane microemulsions in the presence of chloride anionbased ionic liquids ils, such as 1ethyl3methylimidazolium chloride emimcl, 1butyl3methylimidazolium chloride bmimcl, and 1octyl3methylimidazolium chloride omimcl, was investigated. Microemulsions mes are clear, thermodynamically stable systems. Insulinloaded microemulsions for transdermal delivery were developed using isopropyl myristate or oleic acid as the oil phase, tween 80 as the surfactant, and isopropyl alcohol as the cosurfactant. Characterization of microemulsions prepared using isopropyl.
Husein journal of colloid and interface science 316 2007 442450 fig. Tween 20, 40, 60, and 80 were used separately as surfactant with methanol, ethanol, 1propanol, 1butanol or 1pentanol as cosurfactant, and ipp as oil phase to prepare various microemulsions. Enhancing solubilization in microemulsionsstate of the art and current trends article pdf available in journal of surfactants and detergents 81. Previous studies indicate the addition of a linker substance could double the solubilization of the system by segregating at the interface. Nagarajan department of chemical engineering, the pennsylvania state university, 161, fenske laboratory, university park, pennsylvania 16802 received may 11, 1992. Cyclodextrins can, in fact, solubilize and stabilize active compounds, increase their bioavailability. Microemulsions can have characteristic properties such as ultralow interfacial tension, large interfacial area and capacity to solubilize both aqueous and oilsoluble compounds. The influence of chainlength of the alkanes and amines on water solubilization behavior of these systems. While microemulsions are used in several fields, this article focuses on the reported investigations for topical and various other applications which exhibit minimal systemic absorption. The insulin permeation flux of microemulsions containing oleic acid as oil phase through excised.
Compensating changes between formulation variables. Waterinoil microemulsions were produced by mixing different combinations of the cationic surfactants cetyltrimethylammonium bromide and cetylpyridinium chloride, n alkanes c 5 c 7 and benzene as oils, n alkylamines c 6 and c 8 and cyclohexylamine as cosurfactants with water. Formation and solubilization property of waterinoil. Preparation of nano and microemulsions using phase inversion. This volume and its companion volume 2 chronicle the proceed ings of the international symposium on micellization, solubiliza tion, and t1icroemulsions held under the auspices of the northeast regional meeting of the american chemical society in albany, new york, august 811, 1976. Current state of nanoemulsions in drug delivery 627 such phases are actually quite different 4. The structural transitions within the microemulsions and nanoemulsions have also been studied. The dependence of catalytic acitivity on the composition of the system revealed two maxima, in contrast to the behaviour of previously studied enzymes where a single maximum has been observed.
The winsor 2 system is also a twophase system where a wo microemulsion coexists with an excess aqueous phase. This work deals with surfactantfree microemulsions sfme and is composed of two parts. Because of their unique solubilization properties, microemulsions have attracted increasing attention as potential drug delivery systems, either as vehicles for topical applications or as bioavailability enhancers for poorly water soluble active pharmaceutical ingredients api. This book provides an assessment of some issues influencing the characteristics and performance of the microemulsions, as well as their main types of applications. Preparation of nano and microemulsions using phase. Since microemulsions were discovered approximately six decades ago, their applications in several fields, including cosmetics, have been increased due to their good appearance, thermodynamic stability, high solubilization power, and ease of preparation. Development of microemulsion for solubility enhancement of. Microemulsions are readily distinguished from normal emulsions by their transparency, low viscosity and more fundamentally their thermodynamic stability. Pdf enhancing solubilization in microemulsionsstate of. The free energy of microemulsion formation can be considered to depend on the extent to which surfactant. Langmuir 1993,9, 369375 369 polymerinduced structural transitions in microemulsions r. The microemulsions being considered are schematically depicted in figure 1. Control of crystallisation through the use of microemulsions oliver james cook st cuthberts society department of chemistry university of durham september 2012 thesis submitted to the university of durham in partial fulfilment of the regulations for the degree of doctor of philosophy. Waterinoil microemulsions for some dry cleaning processes floor polishers and cleaners.
In addition, microemulsions can enhance skin permeation of the loaded substances. Lyotropic liquid crystals are equilibrium structures comprised of liquids and surfactant, such as lamellar sheets, hexagon ally packed columns, and wormlike micellar phases, that form spontaneously through thermodynamic self assem bly. Along a formulation scan, solubilization is maximal when a bicontinuous microemulsion is in equilibrium with both oil and water excess phases in a socalled winsor iii system. In the first part these kind of ternary systems were investigated as a possible alternative for toxic extraction solvents that are still in use. The rapidly increasing number of applications for microemulsions has kept this relatively old topic still at the top point of research themes.
Single phase microemulsions spmes and in situformed microemulsions may be used to clean up and remove nonpolar materials from reservoir production zones of oil and gas wells. In order to broaden the scope of the symposium, i suggested that the theme of the symposium should be micellization. Improving solubilization in microemulsions with additives. On the other hand, wo microemulsions were determined at the corner of surfactantrich region along dilution lines 1, 2, 3 and 4 in the ternary. The logical way to enhance solubilization is to increase the interaction of the surfactant for both the oil and water phases, which can be easily attained by increasing the size of both the head and tail groups. Microemulsions are singlephased systems formed by the spontaneous solubilization of two otherwise immiscible liquids in the presence of surfactants, with or without the aid of a cosurfactant. Preparation, optimization and characterization of microemulsions microemulsions are isotropic systems, which are difficult to formulate than ordinary emulsions because their formulation is a highly specific process involving.
Microemulsions are monodispersed spherical droplets diameter lt 100 nm of water in oil or oil in water, depending on the nature of the surfactant. Enhanced drug solubilization and improved bioavailability. Colloids and surfaces, 29 1988 1191 119 elsevier science publishers b. Winsor iv systems 1, or microemulsions 2, are macroscopically monophasic fluid transparent compounds made up by mixing water and hydrocarbon in the presence of. Catalytic acitivity and stability of cholesterol oxidase dissolved in ternary systems composed on nhexane, isopropanol, and water were studied. Preparation and evaluation of microemulsion systems. In the second part prestructuring of hydrotropes in water was studied, and its influence on the solubilisation of a third, hydrophobic component. Nanoparticle uptake as a function of aot concentration obtained. Salicylic acid sa is a keratolytic agent used in topical products with antimicrobial actions. The objective of this work was to prepare and evaluate sa me systems. Pdf improving solubilization in microemulsions with. Sep 09, 2009 microemulsions mes are clear, thermodynamically stable systems. The lipophilic linker effect increases the solubilization capacity of the anionic surfactant system.
Properties and applications provides a complete and systematic assessment of all topics affecting microemulsion performance and discusses the fundamental characteristics, t. Enhanced oil solubilization using microemulsions with. Solubilization in microemulsions and application to. The addition of linker molecules enhances the microemulsion solubilization property, which increases the hydrophilicity and or the lipophilicity behavior of surfactants. The addition of linker molecules enhances the microemulsion solubilization property, which increases the hydrophilicity andor the lipophilicity behavior of surfactants. Microemulsion microemulsions are thermodynamically stable dispersions of oil and water stabilized by a surfactant and, in many cases, also a cosurfactant. Sep 30, 2014 uses microemulsions have many commercially important uses. This clean up occurs by solubilization of the nonpolar material into the microemulsion when the treatment fluid contacts the nonpolar material. Nanoparticle uptake as a function of mixing time obtained when mixing a stoichiometric amount of cucl2containing microemulsions.
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