Sarah Sujitha Emulsomes

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EMULSOMES BY Y.SARAH SUJITHA BPHARMACY lV year PRIYADARSHINI COLLEGE OF PHARMACEUTICAL SCIENCES HYDERABAD. 1

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CONTENTS Introduction Advantages Disadvantages Comparison Preparation Characterization Application Present marketed drugs Conclusion Acknowledgment References 2

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INTRODUCTION Emulsomes, having the characteristics of both liposome's and emulsions, provide the advantages of high hydrophobic drug loading in the internal solid lipid core and the ability to encapsulate water-soluble medicaments in the aqueous compartments of surrounding phospholipid layers. Emulsomes proprietary solid fat nano emulsions, represent a novel lipoidal Vehicle of particulate structure with improved loading capacity for drugs and biologics containing components that have been safely used to deliver medications to people. It is a liquid base drug delivery system . It has a wide range of therapeutic application especially for parental delivery of drugs, which are purely water soluble. Emulsomes and other nano particles are special carrier systems for intracellular localization in macrophage rich organs like lever and spleen. 3

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Since lipo phillic drugs have limited water solubility excess quantity of surface active agents or co-solvents are required but it leads to toxic side effects. Emulsomes are distinct from standard oil-in-water emulsions. Due to the high phospholipid content of a monolayer of phospholipid surrounds the lipid core at the aqueous interface thereby stabilizing the emulsion. In addition, one or more bilayers or envelopes of phospholipid molecules are believed to form around the particles in many embodiments. The particle size distribution of emulsomes , based on differential weight percents, is in the range of 10-250 nm, making them suitable for intravenous administration. 4

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5 Lipid compositions of the core are characterized as being in the solid or liquid crystal phase at least 25° C. when measured in bulk form. The present pharmaceutically stable solid fat nanoemulsions or emulsomes may be formulated in the absence of any ionic or non-ionic ,non-natural synthetic surfactant or co-surfactant such as polyoxamers , deoxycholate , poly - sorbates , tyloxapol , or emulphor . They are stabilized by the combination of relatively high lecithin content and the use of solid lipid compositions as the core.

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6 STRUCTURE It has a microscopic lipid assembly with a polar core Which contain water insoluble drugs . Emulsomes comprise a hydrophobic core(composed of solid fats instead of oils ) as in standard oil in water emulsions , but the core is surrounded and stabilized by one or more envelopes of phospholipids bilayers as in liposome's. Phospholipid layer Lipid Core Lipid crown

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7 By using specific combinations of lipids for the emulsomes Internal Coproprietary emulsifications and manufacturing technique, the formation of stable lipid particles 52250 nm in diameter has been achieved . Emulsomes characteristically contain A polar core and Liposomal crown(surface) Phospholipid layer Lipid Core Lipid crown

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8 EMULSION Emulsions are defined as heterogeneous systems of one liquid dispersed in another in the form of droplets usually exceeding 1 μm in diameter. The two liquids are immiscible and chemically unreactive or slowly reactive. An emulsion is a thermodynamically unstable dispersed system. LIPOSOME An artificial microscopic vesicle consisting of an aqueous core enclosed in one or more phospholipid layers, used to convey vaccines, drugs, enzymes, or other substances to target cells or organs. EMULSOME The new entity is a particulate drug vehicle which is denoted herein as a solid fat nanoemulsion or "emulsome.“ These compositions have features which are intermediate between liposomes and oil-in-water emulsions. Particles contain a hydrophobic core, as in standard oil-in-water emulsions, which is surrounded and stabilized by one or more layers or envelopes of phospholipid molecules, as in liposomes.

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9 EVALUATION In vitro In vivo IN-VITRO CHARACTERIZATION Shape & Morphology The shape and surface morphology of the prepared emulsomes as studied by both transmission microscopy and scanning electron microscopy IN-VITRO DRUG RELEASE The in-vitro drug release profiles of zidovudine from different emulsomal formulations were determined using a dialysis tube method . PROCEDURE 2ml formulation taken in a donar compartment & placed in a receptor cell containing 100ml PBS placed on magnetic stirrer at temp 37+1c through out study

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10 Perodically the samples are with drawn and after each with drawl the medium is compensated with fresh PBS The samples are analysed for zidovudine content spectrophotometrically At 266.5nm IN-VIVO TISSUE DISTRIBUTION STUDY 6 Albino rats (100-150g)divided into 2 groups SACRIFICED AFTER 0.5,1,2,4,6,24Hr Visceral organs are removed washed with ringers solution(to remove debries) dried using tissue paper 3 RATS PLAIN ZIDOVUDINE INJECTION WAS ADMINISTERED IV THOUGH THE CAUDAL VEIN (DOSE 5mg/kg) 3 RATS OTHER PREPARATION OF EMULSOMAL FORMULATION IN EQUIVALENT DUG DOSE ARE GIVEN

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11 weighed, minced, homogenized in 2ml of PBS(tissue homogenizer) Tissue homogenates are deprotinized using 10%v/v trichloroacetic acid in water Dark for 30 min filtered through 0.45-micro mt membrane Serum was harvested from collected blood samples , deprotinized in similar way The filtrates were analysed for zidovudine using HPLC method

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12 PREPARATION Emulsomes are prepared by mixing phospholipids and triglycerides in a weight ratio of 0.5:1 (mixing) (PL+TG) (Transition temp 25 0 c) (suspended) In aqueous solution(<25 0 c) then nano emulsion is obtained(10-250nm) dissolve volatile solvents(dichloro methane) (diethyl ether)

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13 Mix them in the vaccume It forms a lipid filim The lipid filim is then hydrated The resulting emulsomes are formed At a size range of 140±15nm

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14 TYPES OF PREPERATIONS Emulsomes can be administered by as fallows: INTRANASSAL ORAL TOPICAL PARENTERAL AEROSAL INHALATION

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15 The size range of 10-250nm of emulsome particle are suitable for the preparation of parental preparation. The nano-emulsion is administered as drops applied to the cornea or at the corners of the eye . Such eye drops are more similar to the parenteral preparation rather than topical preparation . Like parenteral preparation ,preferred emulsions for installation into the eye are sterile and pH should be close to neutral or usual pH should be 6 to 8.

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16 THE COMPOSITION OF EMULSOMES Lipid core Surface active agents LIPID CORE: Triglycerides Cholesteryl esters and cholesterol Monoesters Antioxidants Protein components SURFACE ACTIVE AGENTS: Negatively charged lipids Phospholipids Non-natural surfactants

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17 TRIGLYCERIDES: Triglycerides are a preferred material from which the lipid core may be prepared. The triglyceride core may be composed of a single pure triglyceride, usually available as a synthetic triglyceride, or may be a mixture of several triglycerides. Fats isolated from natural sources usually are available only as mixtures of triglycerides. Such natural mixtures are suitable for preparation of emulsomes, provided that the melting characteristics of the mixture are such that they exhibit a solid or liquid crystal phase at 25° C.

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18 Examples of solid fats suitable for the preparation of emulsomes are triglycerides composed of Natural(tri caprin, trilaurin, trimyristin) even-numbered ,unbranched fatty acids with chain lengths in the C10-C18 range microcrystalline glycerol tri esters of saturated, even-numbered and unbranched fatty acids . In general, any lipid component or mixture of lipid components which provides a solid phase at room temperature (25° C.) when measured in bulk is suitable for the lipid core.

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19 CHOLESTEROL &ESTERS Cholesterol and its esters change the packing structure of lipids, and in high concentrations they induce the formation of a liquid crystal phase. MONOESTERS The lipid or hydrophobic core of emulsomes also may be composed of or contain monoesters of fatty acids, such us waxes. In general, waxes are long chain fatty alcohol esters of fatty acids. Many waxes have suitable melting characteristics for use in emulsomes, since they are solids at 25° C. Eg: beeswax and spermaceti

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20 ANTIOXIDANTS : The lipid cores of emulsion particles of this invention optionally may contain one or more antioxidants. A preferred antioxidant is α- tocopherol or its derivatives, which are members of the Vitamin E family. Other antioxidants include butylated hydroxytoluene (BHT). PROTEIN COMPONENTS: cells Lipid particles preferably do not contain serum apolipoproteins such as apo B, apo AI, apo AII, or apo E. The apo B protein has the effect of targeting intravenously administered lipid particles to certain cellular reoeptors , such as the LDL receptor on hepatocytes and certain other cells In addition, preferred preparations of emulsomes are substantially free of lipase and phospholipase enzymatic activity. As defined herein, an emulsion is "substantially free" of lipase or phospholipase activity if the emulsion lipids or phospholipids are enzymatically cleaved at a rate of less than 0.1% per day when stored at room temperature.

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21 SURFACE ACTIVE MOLECULES The lipid core is surrounded by at least one envelope or layer containing phospholipid molecules. The phospholipid envelope functions as a stabilizer or surface-active agent at the lipid-water interface, thereby lowering the surface tension. In general, the surface-active phospholipid molecules are believed to form a monolayer around the lipid core of the particles, with the polar phospholipid head groups at the aqueous interface. excess phospholipid may be available to form one or more roughly concentric bilayers which encapsulate the lipid core with its associated phospholipid monolayer. The number of bilayer envelopes is variable, and may include one, two, or many bilayers . These bilayer envelopes entrap one or more aqueous compartments which may be made to contain a water-soluble drug by creating the lipid particles in the presence of an aqueous solution of that drug. Although the multiple concentric bilayer model of the structure of emulsomes is proposed because it accounts for the observed ability of the particles to carry high loads of both lipid-soluble and water-soluble drugs.

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22 SURFACE ACTIVE AGENTS Negatively charged lipids Phospholipids Non natural surfactants NEGATIVELY CHARGED LIPIDS Negatively charged lipid molecules such as oleic acid, or negatively charged phospholipids such as phosphatidylglycerol, phosphatidic acid can be added to the lipid phase of emulsomes to increase the zeta potential of the composition, thus stabilizing the particles. Additionally, the incorporation of these negatively charged lipid compounds in emulsomes results in the formation of phospholipid bilayers with opposing charges, thus increasing the loading of water-soluble molecules in the aqueous compartments formed by the phospholipid bilayers surrounding the lipid core PHOSPHOLIPIDS In preferred embodiments, phospholipids which form "normal" phases (i.e., ionic "head" groups facing to the external aqueous phase and lipophillic "tails" facing internally) under physiological conditions of pH and ionic strength comprise at least 50% of the total phospholipids, more preferably at least 75%, most preferably at least 90% on a molar basis

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23 By contrast, phosphatidlylethanolamine has a tendency to form reverse phases, with the polar head groups oriented internally and the lipophilic tails oriented outwardly. Reverse phases also may be formed by cardiolipin or phosphatidic acid in the presence of Ca +2 ions; by phosphatidic acid at pH less than 3.0; and by phosphatidylserine at pH less than 4.0. NON NATURAL SURFACTANTS: Nonnatural surfactants and detergents optionally may be incorporated into emulsomes in small amounts. As used herein, the terms "nonnatural surfactants" or "detergents" include a wide variety of manmade molecules which form micelles in aqueous solution and contain both lipophilic and hydrophilic domains; however, phospholipids which belong to naturally occurring structural type are excluded from this definition, regardless of whether a particular phospholipid is obtained by synthesis or by isolation from natural sources. Eg tweens

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24 ADVANTAGES Low systemic absorption Site-specificity and increased drug levels at injured tissues Reduced toxicity Improved pharmacological activity The use of emulsomes as a drug delivery system has demonstrable advantages, including high loading of problematic drugs that previously could not be administered intravenously in the absence of co solvents or toxic surfactants The solid lipid nanoemulsions of this invention provide effective pharmaceutical delivery for a broad variety of both water-soluble and water-insoluble drugs with minimal local or systemic toxicity

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25 DISADVANTAGES Emulsomes are particularly useful for administration of poorly water-soluble lipophilic drugs which heretofore either could not be administered parenterally or, if so administered, would cause undesirable side-effects. One major drawback of standard oil-in-water emulsions is limited drug loading. When drug encapsulation above 1% is required, a correspondingly larger oil phase (10-20%) is required to dissolve the drug. However, the high oil content reduces the stability of the emulsion, and the addition of a surfactant or cosurfactants, is necessary.

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26 Due to the detergent properties of most surfactant compounds, their use for parenteral administration is very limited. Many toxic reactions have been reported even with the surfactants already approved for intravenous formulations, as in the case of Fungizone® containing sodium deoxycholate .

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27 APPLICATIONS-1 Entrapment of Water-Insoluble Drugs : Incorporation of a Neuroprotectant Drug : All ilpid components +Di chloromethane The organic solvent is evaporated under reduced pressure Using a rotary evaporator To the dry lipid film 50ml of saline is added and the mixture was then hydrated by shaking until all the lipids were homogeneously dispersed in aqueous phase The preparation was then submitted to 15 cycles of high shear homogenization at 800 bar using Micro lab 70 Gaulin Homogenizer.

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28 The formulation was filtered through a 0.2 μm sterile filter membrane and the particle size distribution of the formulation was determined using a N4MD Coulter Particle Size Analyzer An homogeneous population of emulsomes with a mean particle diameter of 153±24 nm was obtained.

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29 APPLICATION-2 Incorporation of a Psycho tropically Active Agent in Emulsomes : All lipid components +Di chloromethane The organic solvent is evaporated under reduced pressure Using a rotary evaporator To the dry lipid film 50ml of saline is added and the mixture was then hydrated by shaking until all the lipids were homogeneously dispersed in aqueous phase The preparation was then submitted to 13 cycles of high shear homogenization at 800 bar using Micro lab 70 Gaulin Homogenizer.

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30 The formulation was filtered through a 0.2 μm sterile filter membrane and the particle size distribution of the formulation was determined using a N4MD Coulter Particle Size Analyzer An homogeneous population of emulsomes with a mean particle diameter of 153±24 nm was obtained.

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31 APPLICATION - 3 Antifungal Drugs :( amphotericin B) Mechanism of action: The interaction of AmB with membrane sterol changes the membrane permeability, which in turn leads to cellular dysfunction and eventually to cell destruction and death. AmB inhibits membrane enzymes like proton ATP ase in fungal cells and Na+/K+-ATP ase in mammalian cells and this inhibitory activity depletes cellular energy reserves and reduces proliferative ability It is an amphoteric compound composed of a hydrophilic poly hydroxyl chain along one side and a lipophilic polygene hydrocarbon chain on the other AmB is poorly soluble in water . The drug became available commercially as Fungizone in 1960 as a colloidal suspension of AmB in which the bile salt deoxycholate was used as the solubilising agent

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32 APPLICATION - 4 AIDS DRUGS Mechanism of Action: Zidovudine , or azidothymidine (AZT), is an approved drug for the treatment of AIDS. The lipophilic characteristics of AZT-CDS limits its solubility in aqueous buffers and therefore lipophilic delivery vehicles are needed, including use of organic cosolvents such as DMSO- polyethylene glycol mixtures, inclusion in macromolecular complexes like cyclodextrins , or incorporation into lipoidal carriers. AZT-CDS has been successfully incorporated into emulsomes , and significantly increased brain levels of AZT were obtained in rats after its intravenous administration.

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33 DRUGS SUCCESSFULLY FORMULATED IN EMULSOMES In animal study, to provide enhanced plasma levels without deleterious side effects include: anti-fungal agents( miconazole,amB ) Beta blockers( timolol ) Anti- biotics Anti-epileptic( phenytoin, dilantin ) Anti- neoplastic ( zidovudin ) Anti-inflammatory AZT-derivatives

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Conclusion Emulsomes, having the characteristics of both liposome and emulsions, comprise a hydrophobic core (composed of solid fats instead of oils ) as in standard oil in water emulsions , but the core is surrounded and stabilized by one or more envelopes of phospholipids bilayers as in liposome's. These may provide the advantages of high hydrophobic drug loading in the internal solid lipid core and the ability to encapsulate water-soluble medicaments in the aqueous compartments of surrounding phospholipid layers. It has a wide range of therapeutic application especially for parental delivery of drugs, which are purely water soluble. Since lipophillic drugs have limited water solubility excess quantity of surface active agents or co-solvents are required but it leads to toxic side effects.

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35 ACKNOWLEDGMENT With deep sense, of gratitude, I express my heartfelt thanks to sri. ASHOK MATETI sir. who has suggested this topic to me and who has given appropriate articles for me . I thank our beloved principle and other staff members for patient listening and for giving valuable suggestions

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36 REFERENCES Vyas S P. Rasika S and Sanyog J. Development and characterization of emulsomes for sustained and targeted delivery of an antiviral agent to liver. Journal of Pharmacy and Pharmacology . 2006, 58; 321-326. Vyas S P and Swati G. Optimizing efficacy of amphotericin B through Nanomodification. International Journal of Nanomedicine . 2006:1(4) 417–432. SURESH P. VYAS, KAPIL K and AMIT K G. Functionalized nanocarrier(s) to image and target fungi infected immune cells. Medical Mycology . 2009, S1_S7, Thomas C V. Robert W K, John R M, Vaniambadi S K, Nabila M W, Carl R A and Deborah L B. HIV-1 Neutralizing Antibodies in the Genital and Respiratory Tracts of Mice Intranasally Immunized with Oligomeric gp160., The journal of Immunology . Febraury, 2011. Eder L R and Maria J M. Drug delivery systems against leishmaniasis? Still an open question. Expert Opin. Drug Deliv . (2008) 5 (7), 805-822. Solid fat nano emulsions- Patent 5662932.

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37 THANK YOU