III||||I|| USOO5576O16A United States Patent (19) 11 Patent Number: 5,576,016 Amselem Et Al
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III||||I|| USOO5576O16A United States Patent (19) 11 Patent Number: 5,576,016 Amselem et al. 45) Date of Patent: Nov. 19, 1996 54). SOLID FAT NANOEMULSIONS AS DRUG Distributions for Clinical Use", Shimon Amselem, Alberto DELIVERY VEHICLES Gabizon, and Yechezkel Barenholz. Methods of Biochemical Analysis, vol. 33, D. Glick, editor, 75 Inventors: Shimon Amselem, Rehovot, Doron J. Wiley & Sons, N.Y., 1988, "Liposomes: Preparation, Friedman, Carmei Yosef, both of Israel Characterization, and Preservation', Dov Lichtenberg and Yechezkel Barenholz. 73) Assignee: Pharmos Corporation, New York, N.Y. Journal of Pharmaceutical Sciences, vol. 79, No. 12, Dec. 1990, "Optimization and Upscaling of Doxorubicin-Con (21) Appl. No.: 63,613 taining Liposomes for Clinical Use', S. Amselem, A. Gabi Zon and Y. Barenholz. (22 Filed: May 18, 1993 CRC Press, Inc., 1993, Liposome Technology, 2nd Ed., (51 Int. Cl.' .............................. A61K 9/127; A61K 9/16 edited by G. Gregoriadis, Ph.D., vol. 1, Chapter 3, p. 49, 52 U.S. Cl. .......................... 424/450; 424/489; 424/490; "Liposome Peparation Using High-Pressure Homogeniz 424/502; 428/402.2 ers', Martin M. Brandl, Dieter Bachmann, Markus Drech 58) Field of Search ..................................... 424/450, 489, sler, and Kurt H. Bauer. 424/490, 497, 45, 427,502; 514/937-943; Elsevier Science Publishers B.V. (Biomedical Division), 428/402.2 1986, Laboratory Techniques in Biochemistry and Molecu lar Biology, vol. 3, part 2, edited by R. H. Burdon and P. H. 56 References Cited van Knippenberg, “Techniques of Lipidology-Isolation, Analysis and Identification of Lipids', 2nd revision edition, U.S. PATENT DOCUMENTS Moris Kates. 5,023,271 6/1991 Vigne ...................................... 514,458 Primary Examiner-Gollamudi S. Kishore 5,171,737 12/1992 Weiner ........................................ 514/3 Attorney, Agent, or Firm-Pennie & Edmonds 5,188,837 2/1993 Domb ...... ... 424/450 5,284,663 2/1994 Speaker ........... ... 424/489 57 ABSTRACT 5,302,401 4/1994 Livensidge ...... ... 424/501 5,306,508 4/1994 Kossovsky ...... ... 424,493 The present invention provides pharmaceutical composi 5,308,624 5/1994 Maincent ................................ 424/427 tions comprising nanoemulsions of particles comprising a lipid core which is in a solid or liquid crystalline phase at 25 FOREIGN PATENT DOCUMENTS C, stabilized by at least one phospholipid envelope, for the 0315079 10/1989 European Pat. Off.. parenteral, oral, intranasal, rectal, or topical delivery of both 0506197 9/1992 European Pat. Off.. fat-soluble and water-soluble drugs. Particles have a mean WO9/07171 5/1991 WIPO. diameter in the range of 10 to 250 nm. A wide variety of drugs and oxygen transporting perfluorocarbons may be OTHER PUBLICATIONS encapsulated in the particles. In addition to drug delivery CRC Press, Inc., Liposome Technology, 2nd Edition, vol. 1, vehicles, the invention provides oxygen transporting blood Chapter 28, p. 501, Liposome Preparation and Related substitutes, and nanoemulsions for extracorporeal mainte Techniques, edited by Gregory Gregoriadis, Ph.D., "A nance of tissues prior to transplantation. Large-Scale Method For The Preparation Of Sterile And Nonpyrogenic Liposomal Formulations Of Defined Size 54 Claims, 3 Drawing Sheets 400 200 1 O OO 800 600 400 EMUSOME 200 40 60 80 TIME (DAYS) U.S. Patent Nov. 19, 1996 Sheet 1 of 3 5,576,016 29%: k 23%: k : k k k 17%: k k Ekk : kick 12%: kick kikk kick ki: 6%: kkk k kick kick : 10E--00 : 6.0E--00 : 4.0E--01 : 2.5E-02 : 1.6E--03 : 10E--04 PARTICLE DIAMETER (NM) FIG. 1 U.S. Patent Nov. 19, 1996 Sheet 2 of 3 5,576,016 1400 1200 1 O O O 800 600 400 EMUSOME 200 O 20 40 60 80 TIME (DAYS) FIG.2 U.S. Patent Nov. 19, 1996 Sheet 3 of 3 5,576,016 O 1 2 3 4 5 6 7 8 TIME (HOURS) FG.3 5,576,016 1. 2 SOLID FAT NANOEMULSIONS AS DRUG The use of parenteral emulsions as drug delivery systems DELIVERY VEHICLES is still comparatively rare because of the necessity of achiev ing stable microdroplets of less than 1 um to prevent formation of emboli in the blood vessels. In order to increase FIELD OF THE INVENTION the stability and useful lifetime of the emulsion, the dis persed lipid droplets must be coated or treated with emul The present invention concerns methods and composi sifiers or "stabilizers,” which lower the free energy at the tions for parenteral and other routes of administration for interface and decrease the tendency of droplets to coalesce. delivery of drugs. More particularly, it concerns stable However, many emulsifiers produce deleterious side effects lipid-in-water emulsions containing small lipid particles 10 upon injection into the body. Due to their detergent charac which are useful as delivery vehicles for both lipid-soluble teristics, most of them are hemolytic agents which act as and water-soluble drugs. membrane solubilizers. Formulation options are severely restricted by the very limited selection of stabilizers and BACKGROUND OF THE INVENTION emulsifiers approved and safe for parenteral injection. Available vehicles for the parenteral administration of 15 The water insolubility of several important drugs, such as water-insoluble compounds often produce undesirable side amphotericin B, phenytoin, miconazole, cyclosporin, diaz effects such as hemolysis, thrombophlebitis, or blood coagul epam, and etoposide, makes their formulation for intrave lation. Liposomes and oil-in-water emulsions have been nous use difficult. These drugs presently are marketed in promoted as potential carriers for fat-soluble materials cosolvent systems such as polyethylene glycol or propylene which minimize such undesirable side-effects. However, 20 glycol-ethanol-benzyl alcohol mixtures. However severe many problems with stability and drug loading capacity toxicity problems, such as thrombophlebitis, have arisen have been reported using either of these delivery systems. with injectable formulations of drugs dissolved in cosol The use of liposomes as drug delivery systems has been vents. Alternatives to cosolvent systems are micellar solu known for some time, and comprehensive review articles on tions or emulsions; but as mentioned above, the presence of their properties and clinical applications are available; see, 25 toxic surfactants in those systems makes them undesirable e.g., Barenholz and Amselem, in "Liposome Technology', for intravenous administration. 2nd ed., G. Gregoriadis, ed., CRC press, 1992; Lichtenberg SUMMARY OF THE INVENTION and Barenholz, in Methods for Biochemical Analysis, 33, D. Glick, ed., 1988. A liposome is defined as a structure The present invention provides pharmaceutical composi consisting of one or more concentric lipid bilayers separated 30 tions comprising nanoemulsions of particles comprising a by water or aqueous buffer compartments. These hollow lipid core composed of lipid which is in a solid or liquid structures, which have an internal aqueous compartment, crystalline phase at at least 25°C., stabilized by at least one can be prepared with diameters ranging from 20 nm to 10 phospholipid envelope, for the parenteral, oral, rectal, intra um. They are classified according to their final size and nasal, or topical delivery of both fat-soluble and water preparation method as: SUV, small unilamellar vesicles 35 soluble drugs. The new entity is a particulate drug vehicle (0.5–50 nm), LUV, large unilamellar vesicles (100 nm); which is denoted herein as a solid fat manoemulsion or REV, reverse phase evaporation vesicles (0.5um); and MLV, "emulsome.' These compositions have features which are large multilamellar vesicles (2-10 um). Drug molecules can intermediate between liposomes and oil-in-water emulsions. be either encapsulated in the enclosed aqueous space or Particles contain a hydrophobic core, as in standard oil-in intercalated into the lipid bilayer. However, the exact loca 40 water emulsions, which is surrounded and stabilized by one tion of the drug in a liposome depends on its physicochemi or more layers or envelopes of phospholipid molecules, as in cal characteristics and the composition of the lipids. liposomes. A key feature of these particles is that the core is com Although effective for sustained release and tissue local posed of lipid which in bulk form is in a solid or liquid ization of drugs, liposomes have the drawback that the 45 amount of drug that can be contained therein is limited. crystalline phase, rather than an oil in a fluid phase. Lipid Furthermore, difficulties are encountered in the preparation compositions of the core are characterized as being in the of pharmaceutically acceptable liposomal formulations with solid or liquid crystal phase at at least 25°C. when measured long term stability and high percentages of drug entrapment. in bulk form. A major limitation of all types of unilamellar vesicles or 50 Emulsomes, having the characteristics of both liposomes single bilayer liposomes is their low drug loading capacity and emulsions, provide the advantages of high hydrophobic for lipophilic compounds, due to their relatively low content drug loading in the internal solid lipid core and the ability to of lipid molecules; therefore they are more suitable for encapsulate water-soluble medicaments in the aqueous com entrapment of water-soluble materials. Although encapsula partments of surrounding phospholipid layers. Emulsomes tion of large amounts of hydrophobic drugs in multilamellar 55 are particularly useful for administration of poorly water liposomes is feasible, they are not appropriate for intrave soluble lipophilic drugs which heretofore either could not be nous administration due to their large size. administered parenterally or, if so administered, would Emulsions are defined as heterogeneous systems of one cause undesirable side-effects. liquid dispersed in another in the form of droplets usually The present pharmaceutically stable solid fat nanoemul exceeding 1 um in diameter. The two liquids are immiscible 60 sions or emulsomes may beformulated in the absence of any and chemically unreactive or slowly reactive. An emulsion ionic or non-ionic nonnatural synthetic surfactant or cosur is a thermodynamically unstable dispersed system.