1. MICRO-EMULSIONS&MULTIPLE EMULSIONSPRESENTED BYCH.Leena madhuri256212886009M.PHARMACY (SEMESTER-II)DEPARTMENT OF PHARMACEUTICS

2. CONTENTSINTRODUCTIONADVANTAGES OF MICRO EMULSIONS ANDMULTIPLE EMULSIONDIFFERENCES BETWEENEMULSION&MICROEMULSIONTYPES OF MICRO EMULSIONS AND MULTIPLEEMULSIONSFORMULATION AND PHASE BEHAVIOURTECHNIQUESAPPLICATIONSCONCLUSIONREFERENCES 3. DEFINITON:- Emulsions are defined as thermodynamically unstableheterogenous systems, in which one immiscible liquidis dispers in another phase in the form of droplets &stabilised by third component called emulsifyingagent. Simple emulsions are 2 types:W/O systemO/W system 4. MicroemulsionsMicroemulsions are thermodynamically stable,optically transparent, isotropic dispersions ofaqueous and hydrocarbon liquids stabilized by aninterfacial film of surfactant moleculesMicroemulsions show diverse structural organizationsdue to wide range of surfactant concentrations, water-oilratios, temperature etc... 5. The surfactant used in these formulations are knownto improve the bioavailability by various mechanismsincludingA) Improved drug dissolutionB) Increased intestinal epithelial permeabilityC) Increased tight junction permeability 6. Advantages of Microemulsions:Micro emulsions are simple and economic.They have long term stability and enhanced bioavailability.High solubilization capacity for hydrophilic and lipophilicdrugs. Various routes like topical, oral and intravenous can be usedto deliver the productMicro emulsions have low viscosity compared to otheremulsions. 7. DIFFERENCES 8. FORMULATION:Microemulsion formulation involves a combination ofthree or five components.a) An oily phaseb) An aqueous phasec) Primary surfactantd) Secondary surfactante) Electrolyte 9. SURFACTANT combination of anionic or cationic surfactants of highHLB with a co- surfactant of low HLB, a single chainnon- ionic surfactant of the poly ethylene glycol alkylether at appropriate temp. are generally used for theformulation of micro emulsion.examples: span 8O,tween 6O,polyoxy ethylene lauryl ethersodium dodecyl sulphate 10. CO-SURFACTANT It is generally not possible to achieve a requiredinterfacial area with the use of single surfactants, ifhowever co- surfactant is added to the system.An essential requirement for the formation and thestability of micro emulsion is attained at very lowinterfacial tension. Since micro emulsion have verylarge interphase between oil and water because ofsmall droplet size, they can only be thermodynamically stable. 11. OILSThe oil component influence curvature by its abilityto penetrate and hence swell the tail group region ofthe surfactant mono layer.Short chain oils penetrate the tail group region tograter extent than long chain alkanes, and hence swellthis region to a grater extent, resulting in an increasingnegative curvatureExample:Triglycerides , lauroglycol, and olive oil. 12. TEMPERATURE:It plays an important role in the formulation ofmicroemulsion when an non-ionic surfactant is used.At low temperature, non-ionic surfactant arehydrophilic and form o/w microemulsion, at hightemperature, they are lipophlic and form w/omicroemulsion.At an intermediate temperature, hydrophilic-lipophilicinteractions just balance and formbicontinuous microemulsion 13. PREPARATION OF MICRO EMULSIONThe drug is be dissolved in the lipophilic part of the microemulsion i.e. Oil and the water phases can be combinedwith surfactant and a co surfactant is then added at slowrate with gradual stirring until the system is transparent.Gel may be prepared by adding a gelling agent to the abovemicro emulsion. Carbomers (crosslinked polyacrylic acidpolymers) are the most widely used gelling agent. 14. PHASE BEHAVIOUR:Oil, water and surfactants are mixed, microemulsions are the one of the number ofassociation structures { including emulsion,lamellar, micelles, cubic and hexagonal} that canform depending up on the composition.A quaternary phase diagram is time consuming .pseudo ternary phase diagram is constructed tofind out the different zones of micro emulsions. 15. In each corner of diagram represents 100% of theparticular component.Micro emulsion can also exists in equilibrium withexcess water, excess oil or both, which are known aswinsor Type 1,2,&3 systems.The winsor type 1 system consists of a lower phase o/wmicro emulsion with excess of oil. 16. Type 2 consists of upper phase of w/o microemulsion with excess of water.Type 3 system form when the surfactant areconcentrated in surfactant rich bicontinuousmiddle phase which co exists with both water andoil. 17. Techniques for characterization ofMicroemulsions:Micro emulsions have been evaluated using a widerange of different techniques: At the microscopic level,viscosity,conductivity anddielectric methods provide useful information.Conductivity measurements provide a means ofdetermining whether a microemulsion is oil-continous orwater-continous and provide a means of monitoringpercolation and phase inversion phenomena. Dielectric measurements are a powerful means of probingboth the structural and dynamic features of microemulsionsystem. 18. Scattering techniques:Small-angle x-ray scattering (SAXS), small-angle neutron scattering(SANS), and static as well as dynamic light scattering are widelyapplied techniques in the study of micro emulsions. Static scattering techniques, the intensity of scattering light aremeasured at various angles and for different concentration of microemulsion droplets. The intensity of scattering radiation is measured asa function of the scattering vector q,Q= (4/) sin/2Where is the scattering angle is the wave length of the radiation These methods are use to obtain quantitative informations on thesize, shape and dynamics of the components. 19. Nuclear Magnetic Resonance Studies:Structure and dynamics of micro emulsion. Self-diffusion measurements using different tracertechniques, generally radio labelling.The Fourier transform pulsed-gradient spin-echo (FT-PGSE)technique uses the magnetic gradient of thesamples. 20. Interfacial tension:The formation and the properties of microemulsioncan be studied by measuring the interfacial tension. Spinning-drop apparatus can be used to measure theultra low interfacial tension. 21. Viscosity Measurements:Viscosity measurements can indicate the presence ofrod like or worm-like reverse micelle.Viscosity measurements as a function of volumefraction have been used to determine the hydrodynamic radius of droplets . 22. Applications of Microemulsions: oral drug delivery Topical drug delivery ocular and pulmonary delivery parenteral administration preflouro microemulsions microemulsions in biotechnology. Solubilization of drugs in microemulsionsinfluence on drug release characteristics 23. Oral Drug Delivery:Micro emulsions extensively studied forprotection of biodegradable drugs. Short half-life, stability, biodegradability of thesemolecules cause considerable design difficulties intheir formulation for oral administration. 24. Example:Cyclosporine is an immunopotent drug widely used intransplants. It has very poor bioavailability after oraladministration.w/o microemulsion were administrated to rat per orallyand it was found that for one of them, the absolute andrelative bioavailability were better than that ofcommercially available solutions.A cyclosporine preparation using w/o microemulsioncontaining a sorbiton ester-polyoxyethylene glycol monoether mixture of surfactant, a low molecular weight alcoholfatty ester and water as the vehicle for the drug wasadministered. 25. Topical drug delivery: Transdermal drug delivery system exhibitsseveral advantages than oral route, by avoidingsystemic side effects.Example: Lecithin containing w/o micro emulsion ofscopolamine and broxaterol was used for thetransdermal administration and found that thetransport rate obtained with the lecithin microemulsion gel was much higher than that obtainedwith an aqueous solution at the sameconcentration. 26. Parenteral Administration: In order to attain prolonged release and to administerparenterally lipophilic substances that are not soluble inwater, o/w micro emulsion may be used as carriers.They can be administrated by intravenous, intramuscular,subcutaneous route. The potential of o/w micro emulsionsas a vector for fluorocarbon, calcium antagonist, steroidsand other lipophilic drugs.o/w microemulsion containing very lipophilic drugs toreticuloendothelial system i.e.. liver and spleen. The resultsindicted that higher the partition coefficient of the drug 27. Micro emulsion in Biotechnology:Many enzymatic and biocatalytic reactions are conductedin pure organic or aqua- organic media.Biphasic media also used for these type of reactions.The use of pure polar media also causes the denaturationof biocatalysts. The use of water-poor media is relativelyadvantageous.Enzymes in low water content display and havea) Increased solubility in nonpolar reactantsb) Improvement of thermal stability of the enzymes 28. MULTIPLE EMULSION Multiple emulsions are novel drug delivery systems, in whichthe dispersed phase contain smaller droplets that have the samecomposition as the external phase. They also called as double emulsion systems /liquidmembrane systems 29. TYPES OF MULTIPLE EMULSIONS:a)oil-in-water-in oil(O/W/O) emulsion systemb)water-in-oil-in water(W/O/W) emulsion system(a) W/O/W double emulsion (b)O/W/O double emulsion37 30. PRINCIPLES OF LIQUID SURFACTANTMEMBRANE EMULSIONS In W/O/W emulsion ,2 miscible aqueous phases separated byorganic phase is called liquid membrane. It is composed of hydrocarbon solvent, emulsifier, additives. It must satisfy 2 primary requirements: It must have ability to form stable emulsion It must have negligible effect on drug activity38 31. METHODS OF PREPARATION Two step emulsification(double emulsification):39 32. Modified two step emulsification technique: The composition of internal aqueous phase oily phase externalphase is fixed at 1:4:5 to produce stable W/O/W emulsion.40 33. Phase inversion technique (one step technique):41 34. MECHANICAL EQUIPMENTS USED FOR EMULSIFICATION PROCESS A)LABORATORY SCALEHOMOGENIZER B)COLLOIDAL MILL C)ULTRA SONIFIER D)LARGE SCALE HOMOGENIZER USED ININDUSTRIES 35. METHODS TO STABILIZEMULTIPLE EMULSIONS Liquid crystal stabilized multiple emulsion Stabilization in presence of electrolytes Stabilization by forming polymeric gel Stabilization by interfacial complexation between non-ionicsurfactant and macromolecules Phase-inversion stabilization of W/O/W emulsion43 36. APPLICATIONS IN THERAPEUTICS ANDCOSMETICS Controlled and sustained drug delivery of various drugs Targeting of bioactives Vaccine adjuvants Multiple emulsions for local immuno suppression Enhancement of absorption Delivery of proteins and peptides Haemoglobin multiple emulsion for oxygen delivery Enzyme immobilization44 37. Conclusion Micro emulsion properties are extremely varied. Theextreme diversity of their practical applications is oneconsequence. One of their disadvantages is the large amount ofsurfactant required to stabilize them because of the smalldispersion size. Although micro emulsion properties are beginningto be satisfactorily understood, especially the dropletstructure, large research domains remain to be clarified. With evaluation of newer techniques of preparation,stabilization, rheological properties can serves as potentialcarrier for drugs ,cosmetics ,pharmaceutical agents 38. REFERENCES S.P. Vyas , R.K. Khar. Targeted & Controlled drugdelivery: novel carrier systems , 1st ed. New Delhi: CBSpublishers ; 2004,page no 303-303 Micro emulsions as drug delivery system,A.NLalwani,T.J shah&N.S Parmar-309 Targeted &Controlled Drug delivery vyas/khar-303 Progress in controlled and novel drug delivery system-nkjain Advance in controlled &drug delivery A.j khapae&N.Kjain-381 39. THANK YOU