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SEMINAR ON SEMINAR ON …….. LIPOSOMES AND NANOTECHNOLOGY PRESENTED BY: MAHESH DABHI Department Of Pharmaceutics and Pharmaceutical Technology, L.M. College of Pharmacy. List of contents o Introduction: o Advantages with use of liposomes as drug delivery system. o Classification o Manufacturing of liposomes o Liposome characterization and control o Stability consideration for liposomal formulations o Regulatory science of liposome drug products o Drug release from liposomes o Applications o Recent innovations o Approved liposome products o References INTRODUCTION o The preparation of liposomes, with entrapped solutes, was demonstrated for the first time in 1965 by Prof. A.D. Bangham of the United Kingdom. Definition o “Liposomes are microscopic spheres made from fatty materials, predominantly phospholipids. o “made up of one or more concentric lipid bilayers, and range in size from 50 nanometers to several micrometers in diameter” Advantages with liposomes o Suitable for delivery of hydrophobic, hydrophilic and amphipatic drugs and agents o Chemically and physically well characterized entities o Biocompatible o Suitable for controlled release o Suitable to give localized action in particular tissues. o Suitable to administer via various routes Classification o Classification based on size of liposomes o Classification based on method of preparation o Classification based on composition and in vivo application Classification based on size Small unilamellar vesicles Medium sized unilamellar vesicles Large unilamellar vesicles Giant unilamellar vesicles Unilamellar vesicles Oligolamellar vesicles Multilamellar large vesicles Multivesicular vesicles Classification based on method of preparation o o o o Vesicles prepared by extrusion method. Vesicles prepared by French press. Vesicles prepared by fusion. Vesicles prepared by reverse phase evaporation. o Frozen and thawed MLV. o Dehydration and rehydration vesicles. o Stable plurilamellar vesicles. Classification based on specific properties o Conventional Liposomes Long circulating liposomes (Stealth Technology) o PEG coating o Low permeability liquid matrix and internal aqueous buffer system Targeted liposomes o Target specific ligands, such as antibodies, immunoglobulins, lectins and oligosaccharides attached to the surface Cationic Liposomes o Cationic lipid component interact with negatively- charged DNA o Results into Lipid –DNA Complexes Temperature sensitive liposome PH sensitive Liposomes MANUFACTURING OF LIPOSOMES Materials used in preparation of liposomes o o o o o o o o Phospholipids Synthetic Phospholipids Glycerolipids Sphingolipids Glycosphingolipids Steroids Polymeric material Charge-inducing lipids Structure of phospholipids Issues to consider when selecting lipids. o o o o o o Phase transition temperature Stability Charge Lipid mixtures Cholesterol Source Preparation of Liposomes Mechanism of Vesicle Formation o The budding theory o The bilayer phospholipids theory The budding theory o Stress induced hydration of phospholipids o Organization in to lamellar arrays o Results in to budding of lipid bilayer leading to down sizing SUV OLV The bilayer phospholipids theory o Liposomes are formed when thin lipid films are hydrated o The hydrated lipid sheets detach during agitation and self-close to form large, multilamellar vesicles (LMV) Method of Liposome Preparation Conventional liposome preparation methods Phospholipids Cholesterol Antioxidant Lipid component compounding Pyrogen yes Lipid solvent Drug ,Salt Antioxidant Buffer WFI Ultrafilter Filter No Filter Solvent recovery Solvent removal Hydration Extrusion Down sizing Free drug recovery Free drug removal Prefilter Sterile filter Vial filling Aseptic processing Lyophollization Seal / package Method for preparation of (SUV) o o o Sonication High shear fragmentation Solvent injection method o Injection of water immiscible solvent. o o o Ether infusion. Fluorocarbon injection. Injection of water miscible solvent. o o Ethanol injection Modified ethanol injection method High shear fragmentation Piston Cell body Rubber-O-ring Pressure relief valve Aqueous samples Closure plug Fig. French pressure cell Outlet Solvent injection method. Ether/lipid solution Vacuum pump Gasket Mix Aqueous phase Temperature Controlled bath Mechanical drive Infusion pump Large and Intermediate sized unilamellar vesicles. o Methods used to prepare LUV and IUV o o o o o o Detergent dialysis Water in oil emulsion technique Freeze thaw cycling Slow swelling in non electrolytes Dehydration followed by rehydration Dilution or dialysis of lipids in the presence of chaotropic ions. Reverse phase evaporation technique. Lipid in solvent solution REV liposomes Two-phase system Gel formation Water in oil emulsion Solvent removal High pressure extrusion. Methods for controlling liposome size o Fractionation o Centrifugation o Size exclusion chromatography o Homogenization o Capillary pore membrane extrusion o Ceramic extrusion Liposome characterization and control Liposomes Characterized by Size Number of lamellae Stability Charge Determined by Preparation Raw materials Protection Classified by Hydration methods Sizing method Degree of saturation Head group Presence of sterols Protecting agents Physical characterization parameters o Mean size and size distribution o Number of lamellae o Osmotic behavior and entrapped volume o Internal distribution of drug o Structural and motional behavior of lipids o Electrical surface potential & Surface PH Stability consideration o Stabilization aspect for physical instability of liposomes o Chemical stability o Biological stability of liposomes Regulatory aspects o Safety concerns: liposome formulation o Lipid toxicity (RBC lysis) o Presence of protein and lipoprotein for natural lipids o Residual solvent o Overload of RES o Particle size o (tail above 1 um) - Blockage of capillaries o Size affects RES uptake and tissue targeting o Stability: shelf-live and in vivo o Dose dumping (via protein binding) o Sterility Drug release from liposomes o The lipid bilayer of the liposome can fuse with other bilayers (e.g. cell membrane) thus delivering the liposome contents. Liposome Performance – In Vitro Release and Stability o In vitro drug release from liposomal systems was determined using dialysis sacks. o Release test for a targeted liposome would need to show that liposome is stable until uptake at the site. Factors affecting release of drug o o o o o o o o o Solvents pH Temperature Agitation Enzymes Cell culture Sink conditions Volume Sampling interval Applications o Liposomes as Protein Carriers in Immunology o Oral Drug Delivery o Site Specific Delivery o Sustained or Controlled Delivery o Gene Therapeutics Applications Innovations in vesicular drug delivery systems o Provesicles in drug delivery systems o o o o o Provesicles in drug delivery systems Proliposomes :Dry granular liposomes Mixed micellar proliposomes Protransferosomes Characterization of provesicular system o Morphology o Angle of repose o Size and size distribution o Rate of hydration o Entrapment efficiency o Degree of deformability and permeability measurement o In vitro release rate o In vivo fate and pharmacokinetic Lipopolyplexes o A combination of DNA, polymers and liposomes o This method has resulted in better gene transfer and lower toxicity as compare to cationic liposomes Transferosomes o Modified liposomes developed to increase the transdermal permeation of drug o Deformability is achieved by using surface active agent in proper ratio o Concentration of surfactant is very crucial Ethosomes o Composed of phospholipids & alcohol ( ethanol or IPA) o Sometimes polyols or glycols in relatively high concentration & water o Better membrane permeability o Discomes o Virosomes o Emulsomes Cochleates o Cochleates are cigar-like microstructures o Consist of a series of lipid bilayers which are formed as a result of the condensation of small unilamellar negatively charged liposomes. Depofoam technology o Depofoam particles include hundred of bilayer enclosed aqueous compound. o Formed by first emulsifying a mixture of an aq phase containing the compound to be encapsulated & an organic phase containing lipid. Niosomes o Nonionic surfactant vesicles(NSV) o Niosomes are formed from the self assembly of non-ionic amphiphiles in aqueous media resulting in closed bilayer. Preparation of Liposomes by dry film method o Lipids and drug dissolved in CHCl3 and evaporated to form thin film o Film is hydrated with buffer solution o Sonicated to form large unilamellar vesicles Preparation of Liposomes by dry film method Lipid + drug + CHCl3 Rotary evaporation Sonication LUV Thin film Approved liposome products marketed in US Doxil Daunorubicin Alza Corporation Kopasi sarcoma Daunoxome Daunorubicin Gilead sciences ,, Ambisome Amphotericin B ,, Serious fungal infection Approved lipid complex products Ambelcet Amphotec Amphotericin B Amphotericin B Alza corporation Elan corporation NANOTECHNOLOGY IN DRUG DELIVERY List of contents o INTRODUCTION o NANOPARTICLES o o History o Types of nanoparticles o Materials and methods o Method of preparation for Nanoparticles o Drug loading into nanoparticles NANOSUSPENSION o Method of preparation for Nanosuspension o Purification of Nanosuspension o CHARACTERIZATION AND EVALUATION OF o NANOPARTICLES AND NANOSUSPENSION. o APPLICATIONS OF NANOPARTICLES AND NANOSUSPENSIONS o NANOSUSPENSION BASED FORMULATION IN DEVELOPMENT AND IN THE MARKET INTRODUCTION o NANOSUSPENSIONS : o are colloidal dispersions of nano sized drug particle that are produced by suitable method and stabilized by suitable stabilizer . o NANOPARTICLES : o They are solid colloidal particles sized from 1-1000 nm . o NANOSPHERES : o polymer matrices in which drug is dissolved or dispersed . o NANOCAPSULES : o consists of polymer wall entrapping an oily core in which the drug is dissolved History o Developed by spieser and co-workers in the late 1960s. o In early 1970s the cross linked polyacrylamide nanoparticles were produced. o Widder at el incorporated magnetic particles into the nanoparticles for targeting of these particles by means of magnetic field. Types of nanoparticles o Monolithic type o Capsule type Monolithic type Capsule type Polymers used in preparation. o Polymethyl methacrylate copolymers, o Polymethyl cyanoacrylate, o Polybutyl cyanoacrylate & Polyisobutyl cyanoacrylate, o Polyhexyl cyanoacrylate & polyisohexyl cyanoacrylate, o Poly(Nα,N-L-lysinedylterephthalamide o Polyisobutyl cyanoacrylate o Poly-D,L-lactide o Serum albumin o Gelatin o Polyacryl dextran o Polyacryl starch o Albumin o Polylactic acid-poly glycolic acid copolymer o Poly(-hydroxy butyrate) o Ethyl cellulose o Eudragit RL,RS Method of preparation for Nanoparticles o Emulsion polymerization o Continuous aqueous phase o One of the most rapid method o The monomer is dissolved in an aqueous phase o The polymerization process is initiated by radiation, UV, or strong visible light o Continuous organic phase Denaturation of natural molecules in an oil emulsion. o Requires emulsification of a natural macromolecule and the drug o The particles are hardened by o Heat denaturation, o Cooing below the gelation point, o Cross-linking with suitable reagent. o Disolvation of macromolecules. o This process is commonly known as coacervation. o Solvent evaporation Drug loading into nanoparticles o Drug may be loaded at two stageso Prior to the preparation of nanoparticles o Addition to the previously prepared particles NANOSUSPENSION o Colloidal dispersions of nanosized drug particle produced by suitable method and stabilized by suitable stabilizer . Method of preparation for Nanosuspension o Media milling (Nanocrystals) Milling chamber Milling Shaft Drug, water & stabilizer Screen retaining milling media in chamber Milling media High Pressure Homogenizers o Size reduction depends upon: o Homogenization pressure o No. of homogenization cycle CHARACTERIZATION AND EVALUATION Physicochemical Characterization o Particle size o Molecular Weight Density o Crystallinity o Surface charge o Hydrophobicity o Surface properties o Surface element analysis Drug release o Side by side diffusion cells with artificial or biological membrane. o Dialysis bag diffusion o Reverse dialysis o Ultra centrifugation o Ultra filtration o Gel filtration o Centrifugal Ultra filtration APPLICATIONS o o o o o Oral Drug Delivery Parenteral Drug Delivery Ocular Drug Delivery Pulmonary drug delivery Targeted drug delivery NANOSUSPENSION BASED FORMULATION Drug Status Paclitaxel Phase III Rapamune Marketed Emend Marketed Cytokine Inhibitor Phase II Thymectacin Phase I & II Busulfan Phase I Budesonide Phase I References o o o o o A.D. Bangham , J. Mol. Biol. 13:238-252, 1965 Ali Demir Sezer,Ahmet Levent Bas, and Ju¨ lide Akbug, Encapsulation of Enrofloxacin in Liposomes I: Preparation and In Vitro Characterization of LUV, Journal of liposome research,Vol. 14, Nos. 1 & 2, pp. 77–86, 2004 Xuedong Yen, Gerrit L. Scherphof, And Jan A. A. M. Kamps, Liposome Opsonization, Journal of Liposome Research, 15:109–139, 2005 Ilya Koltover, Tim Salditt, Joachim O. Radler, An Inverted Hexagonal Phase of Cationic Liposome±DNA Complexes Related to DNA Release and Delivery, 3 July 1998, vol.281 SCIENCE,www.sciencemeg.org Yasuyuki Sadzuka, Kaori Kishi, Sadao Hirota, and Takashi Sonobe, Effect of Polyethyleneglycol (PEG) Chain on Cell Uptake of PEG-Modified Liposomes Journal Of Liposome Research Vol. 13, No. 2, pp. 157–172, 2003. References o o o o Lee Leserman, Liposomes as Protein Carriers in Immunology, Journal Of Liposome Research, Vol. 14, Nos. 3 & 4, pp. 175–189, 2004. Loisel S, Le Gall C, Doucet L, Ferec C, Floch V. Contribution of plasmid DNA to hepatotoxicity after systemic administration of lipoplexes. Hum Gene Ther 2001; 12:685– 696. Pasquale Stano, Simone Bufali,Claudio Pisano, Federica Bucci,Marcella Barbarino, Mose` Santaniello, Paolo Carminati, and Pier Luigi Luisi Novel Camptothecin Analogue (Gimatecan)-Containing Liposomes Prepared by the Ethanol Injection Method, Journal Of Liposome Research, Vol. 14, Nos. 1 & 2, pp. 87–109, 2004 Maria A Stuchlyt, Stan S StuchlyS, Robert P LiburdyO and Daniel A RousseauS, Dielectric properties of liposome vesicles at the phase Transition, Phys. Med. Biol., 1988, Vol. 33, No 11, 1309-1324. References o o o o o Andreas Wagner, Karola Vorauer-Uhl, Gunther Kreismayr, and Hermann Katinger enhanced protein loading into liposomes by the multiple crossflow injection technique, Journal Of Liposome Research Vol. 12, No. 3, pp. 271–283, 2002. Maoquan Chu1, and Guojie Liu, Preparation and characterization of hydroxyapatite/liposome core–shell nanocomposites, Nanotechnology 16 (2005) 1208–1212. Ellens, H., Bentz, J., and Szoka, F.C., Destabilization of phosphatidylethanolamine liposomes at the hexagonal phase transition temperature, Biochemistry, 25, 285, 1986. Kensil, C.R. and Dennis, E.A., Alkaline hydrolysis of phospholipids in model membranes and the dependence on their state of aggregation, Biochemistry, 20, 6079, 1981. Grit, M., de Smidt, J.H., Struijke, A., and Crommelin, D.J.A., Hydrolysis of phosphatidylcholine in aqueous liposome dispersions, Int. J. Pharm., 50, 1, 1989. References o o o o o o o Yoshie Maitani, Hiroshi Soeda, Wan Junping, And Kozo Takayama Modified ethanol injection method for liposomes containing _-sitosterol-d-glucoside, Journal Of Liposome Research, 11(1), 115–125 (2001). Shangguan et.al , 2000, Gene Ther., 7, 769. Liposome Technology Volume 1 : Gregory Gregoridis Pg No . 250 – 255 . Pharmaceutical Dosage Form : Disperse System Vol . 3 Pg No . 148 – 150 . Encyclopaedia : Pharmaceutical Technology Vol 9 Pg No . 1 – 38 . Modified Release Drug Delivery Technology Cha. 58 Stealth Technology . Modified Release Drug Delivery Technology Cha. 47 SLN and Lipopearl for Topical and Controlled Release . References o o o o o o o o Nanosuspensions : A promising drug delivery strategy from JPP , Vol 56 , 2004 , Pg No. 827 – 840 . Microencapsulation : Methods and Application by Simon Benita Cha . 10 , 11 , 12 . Drug Delivery and Industrial Pharmacy : Liposomal as a Drug Delivery System . 1989 Pg No. 1523 , 1989 Pg No. 197 , Pg 387 Vol 3 Depofoam : JPS Nov 1998 , pg 1341 . Eastern Pharmacist : March 1994 , Pg No. 61 . Indian Journal of Pharmaceutical Sciences : Jan-Feb 2004 Pg 121-122 . Journal of Pharmaceutical Science : Vol 90 , No.6 , June 2001 . Journal Of Pharmaceutical Science : Vol 92 , No.1,Pg 6164 January 2003 .