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Nanoparticles and liposomes ppt


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nanoparicles and liposomes molecular pharmaceutics

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Nanoparticles and liposomes ppt

  2. 2. Contents Page 1.Targeting methods Introduction 2. Nanoparticles Types Preparation Evaluation 3. Liposomes Preparation Evaluation Applications
  3. 3. Syllabus Targeting Methods: introduction preparation and evaluation. Nano Particles & Liposomes:Types,preparation and evaluation.
  4. 4. INTRODUCTION TARGETING METHODS. . A special form of drug delivery system where the pharmacologically active agent or medicament is selectively targeted or delivered only to its site of action or absorption and not to the non-target organs or tissues or cells.
  5. 5. Cont… . Targeted drug delivery implies for selective and effective localization of pharmacologically active moiety at pre identified (preselected) target in therapeutic concentration, while restricting its access to non-target normal cellular linings, thus minimizing toxic effects and maximizing therapeutic index.
  6. 6. ADVANTAGES • Drug administration protocols may be simplified. • Drug quantity may be greatly reduced as well as the cost of therapy. • Drug concentration in the required sites can be sharply increased without negative effects on non-target compartments.
  7. 7. DIS ADVANTAGES • Rapid clearance of targeted systems. • Immune reactions against intravenous administered carrier systems. • Insufficient localization of targeted systems into tumour cells. • Diffusion and redistribution of released drugs.
  8. 8. CHARACTERISTICS . Targeted drug delivery system should be- biochemically inert (non-toxic), non- immunogenic. . Both physically and chemically stable in vivo and in vitro. . Restrict drug distribution to target cells or tissues or organs and should have uniform capillary distribution. . Controllable and predictable rate of drug release.
  10. 10. NANO PARTICLES . Nanoparticles (NPs) are defined as particulate dispersions or solid particles drug carrier that may or may not be biodegradable. . The drug is dissolved, entrapped, encapsulated or attached to a nanoparticle matrix. . The term nanoparticle is a combined name for both nanospheres and nanocapsules.
  11. 11. Cont… . Drug is confined to a cavity surrounded by a unique polymer membrane called nanocapsules, while nanospheres are matrix systems in which the drug is physically and uniformly dispersed.
  12. 12. Advantages of Nanoparticles .Nanoparticles have many significant advantage over conventional and traditional drug delivery system. .Nanoparticles are control and sustain release form at the site of localization, they alter organ distribution of drug compound. .They enhance drug circulation in blood, bioavailability, therapeutic efficacy and reduce side effects.
  13. 13. Cont… . Nanoparticles can be administer by various routes including oral, nasal, parenteral, intra-ocular etc. . In the tiny areas of body nanoparticles shows better drug delivery as compare to other dosage form and target to a particular cell type or receptor.
  14. 14. Cont… . Nanoparticle enhance the aqueous solubility of poorly soluble drug, which improves bioavailability of drug. . As a targeted drug carrier nanoparticles reduce drug toxicity and enhance efficient drug distribution. . Useful to diagnose various diseases. . Enhanced stability of ingredients.
  15. 15. PREPARATION TECHNIQUES 1. Solvent Evaporation. . Solvent evaporation method first developed for preparation of nanoparticles. . In this method firstly nanoemulsion formulation prepared. . Polymer dissolved in organic solvent (dichloromethane, chloroform or ethyl acetate). . Drug is dispersed in this solution.
  16. 16. . Then this mixuture emulsified in an aqueous phase containing surfactant (polysorbates, poloxamers,polyvinyl alcohol,). . This make an oil in water emulsion by using mechanical stirring, sonication, or micro fluidization (high-pressure homogenization through narrow channels).
  17. 17. . Representation of the solvent – evaporation technique.
  18. 18. Double Emulsification Method . Emulsification and evaporation method have limitation of poor entrapment of hydrophilic drugs, hence double emulsification technique is used. . Firstly w/o emulsion prepared by addition of aqueous drug solution to organic polymer solution with continuous stirring.
  19. 19. CONT… . This prepared emulsion another aqueous phase with vigorous stirring, resultant w/o/w emulsion prepared.then organic solvent removed by high centrifugation.
  20. 20. Emulsions - Diffusion Method. • This method patent by Leroux et al it is modified form of salting out method. • Polymer dissolved in water-miscible solvent (propylene carbonate, benzyl alcohol), this solution saturated with water. • Polymer-water saturated solvent phase is emulsified in an aqueous solution containing stabilizer. Then solvent removed by evaporation or filtration
  21. 21. . Representation of the emulsification diffusion technique.
  22. 22. Nano precipitation method. . In this method precipitation of polymer and drug obtained from organic solvent and the organic solvent diffused in to the aqueous medium with or without presence of surfactant. . Firstly drug was dissolved in water, and then cosolvent (acetone used for make inner phase more homogeneous) was added into this solution.
  23. 23. CONT... • Then another solution of polymer (ethyl cellulose, eudragit) and propylene glycol with chloroform prepared, and this solution was dispersed to the drug solution. • This dispersion was slowly added to 10 ml of 70% aqueous ethanol solution.
  24. 24. • After 5 minutes of mixing, the organic solvents were removed by evaporation at 35°under normal pressure, nanoparticles were separated by using cooling centrifuge (10000 rpm for 20 min), supernatant were removed and nanoparticles washed with water and dried at room temperature in a desicator.
  25. 25. Coacervation method. . Drug and protein solution (2% w/v) incubated for one hour at room temperature and pH adjusted to 5.5 by using 1M HCl. . In this solution ethanol was added in 2:1 ratio (v/v) in a controle rate 1ml/min. . Resultant coacervate hardened with 25% glutaraldehyde (1.56 μg/mg of protein) for 2 hours which allow cross-linking of protein.
  26. 26. CONT… • Rotary Vacuum evaporation at reduced pressure organic solvents were removed then nanoparticle were collected and purified by centrifugation at four degree centigrade. • Pellets of nanoparticles were then suspended in phosphate buffer (pH 7.4; 0.1 M) and lyophilized with mannitol.
  27. 27. • Salting Out Method. • Salting out method is very close to solvent- diffusion method. • This technique is based on the separation of water-miscible solvent from aqueous solution by salting out effect. • In this method toxic solvents are not used. • Generally acetone is used because it is totally miscible with water and easily removed.
  28. 28. . Polymer and drug dissolved in a solvent which emulsified into a aqueous solution containing salting out agent (electrolytes, such as magnesium chloride and calcium chloride, or nonelectrolytes such as sucrose).
  29. 29. DIALYSIS. Dialysis is an effective method for preparation of nanparticles. In this method firstly polymer (such as Poly(benzyl- glutamate)-b-poly(ethylene oxide), Poly(lactide) and drug dissolved in a organic solvent. This solution added to a dialysis tube and dialysis performed.
  30. 30. Evaluation Parameters Of Nanoparticles Yield of Nanoparticles. % Yield = amount of nanoparticle 100 amount of drug + polymer . The yield of nanoparticles was determined by comparing the whole weight of nanoparticles formed against the combined weight of the copolymer and drug.
  31. 31. Particle Size and Zeta Potential. • Value of Particle size and Zeta Potential prepared nanoparticles determined by using Malvern Zetasizer. Surface Morphology. • Surface morphology study carried out by Scanning Electron Microscopy (SEM) of prepared nanoparticle.
  32. 32. Polydispersity index. • Polydispersity index of prepared nanoparticles was carried out by using Malvern Zetasizer. In-vitro release Study. • In-vitro drug release studies were performed in USP Type II dissolution apparatus at rotation speed of 50 rpm. • The prepared immersed in 900ml of phosphate buffer solution in a vessel, and temperature was maintained at 37±0.20°C.
  33. 33. CONT… • Required quantity 5ml of the medium was withdrawn at specific time periods and the same volume of dissolution medium was replaced in the flask to maintain a constant volume. • The withdrawn samples were analyzed using UV spectrophotometer.
  34. 34. Kinetic Study. . Study of nanoparticles were fitted with various kinetic equation like . zero order (cumulative % release vs. time) . first order (log % drug remaining vs time) . Higuchi s model (cumulative % drug release vs.‟ square root of time).
  35. 35. Stability of Nanoparticles. • Stability studies of prepared nanoparticles determined by storing optimized formulation at 4°C ±1°C and 30°C ± 2°C in stability chamber for 90 days. • The samples were analyzed after a time period like at 0, 1, 2, and 3 months for their drug content, drug release rate (t-50%) as well as any changes in their physical appearance.
  36. 36. TYPES OF NANOPARTICLES . Nanoparticles can be classified into different types according to the size, morphology, physical and chemical properties. Some of them are; 1.Carbon-based nanoparticles. 2.Ceramic nanoparticles. 3.Metal nanoparticles. 4.Semiconductor nanoparticles.
  37. 37. CONT… • Polymeric nanoparticles. • Lipid-based nanoparticles. 1. Carbon-based nanoparticles: . Carbon-based nanoparticles include two main materials: a. Carbon nanotubes (CNTs). b. Fullerenes.
  38. 38. • CNTs are nothing but graphene sheets rolled into a tube. These materials are mainly used for the structural reinforcement as they are 100 times. Where as; • Fullerenes are the allotropes of carbon having a structure of hollow cage of sixty or more carbon atoms. The structure of C-60 is also called Buckminsterfullerene.
  39. 39. Ceramic Nanoparticles • Ceramic nanoparticles are inorganic solids made up of oxides, carbides, carbonates and phosphates. • These nanoparticles have high heat resistance and chemical inertness. • They have applications in photocatalysis, photodegradation of dyes, drug delivery, and imaging.
  40. 40. Metal Nanoparticles • Metal nanoparticles are prepared from metal precursors. • These nanoparticles can be synthesized by chemical, electrochemical, or photochemical methods. • These nanoparticles have applications in detection and imaging of biomolecules and in environmental and bioanalytical applications.
  41. 41. Semiconductor Nanoparticles • Semiconductor nanoparticles have properties like those of metals and non-metals. • These particles have wide bandgaps, which on tuning shows different properties. • They are used in photocatalysis, electronics devices, photo-optics and water splitting applications. • Some examples are Gan,Gap,Inp etc.from group III
  42. 42. Polymeric Nanoparticles • Polymeric nanoparticles are organic based nanoparticles. • Depending upon the method of preparation, these have structures shaped like nanocapsular or nanospheres. • A nanosphere particle has a matrix-like structure whereas the nanocapsular particle has core-shell morphology.
  43. 43. Lipid-Based Nanoparticles • Lipid nanoparticles are generally spherical in shape with a diameter ranging from 10 to 100nm. • It consists of a solid core made of lipid and a matrix containing soluble lipophilic molecules. • The external core of these nanoparticles is stabilized by surfactants and emulsifiers.
  44. 44. Liposomes
  45. 45. Liposomes are concentric bilayered vesicles in which an aqueous core is entirely enclosed by a membranous lipid bilayer mainly composed of natural or synthetic phospholipids.
  46. 46. The size of a liposome ranges from some 20 nm up to several micrometers.
  47. 47. Basic structure of liposome
  48. 48. Lamella . A Lamella is a flat plate like structure that appears during the formation of liposomes. . The phospholipids bilayer first exists as a lamella before getting converted into spheres. . Several lamella of phospholipids bilayers are stacked one on top of the other during formation of liposomes to form a multilamellar structure.
  49. 49. . Small unilamellar vesicle. . Large unilamellar vesicle. . Multi lamellar vesicle.
  50. 50. Advantages of liposomes . Provides selective passive targeting to tumor tissues . Increased efficacy and therapeutic index. . Increased stability of encapsulated drug. . Reduction in toxicity of the encapsulated agent. . Improved pharmacokinetic effects. . Site avoidance effect (avoids non-target tissues).
  51. 51. Disadvantages . Physical/ chemical stability. . Very high production cost. . Drug leakage/ entrapment/ drug fusion. . Sterilization. . Short biological activity / t ½. .Oxidation of bilayer phospholipids. . Overcoming resistance. .Repeated iv administration problems.
  52. 52. Preparation of liposomes Methods of liposome preparation . Passive loading: Involves loading of the entrapped agents before or during the manufacturing procedure. . Active or remote loading: Certain types of compounds with ionisable groups and those with both manufacturing procedure lipid and water solubility can be introduced into the liposomes after the formation of the intact vesicles.
  53. 53. Methods of liposome preparation Passive Loading techniques. . It comprises of three different types. 1.Mechanical dispersion methods. 2. Solvent dispersion method. 3.Detergent removal method.
  54. 54. 1. Mechanical dispersion method . Lipid film hydration by hand shaking non- hand shaking and freeze drying. .Micro emulsification. .Sonication . .French pressure cell. .Membrane extrusion. .Dried reconstituted vesicles. .Freeze thawed liposomes
  55. 55. 2. Solvent dispersion methods .Ethanol injection. .Ether injection. .Double emulsion vesicles. .Stable plurilamellar. .Vesicles. .Reverse phase evaporation vesicles.
  56. 56. Detergent removal methods .Detergent(Cholate,Alkyl glycoside,Triton X-100) removal from mixed micelles by, .Dialysis. .Column chromatography. .Dilution. .Reconstituted sendai virus enveloped vesicles.
  57. 57. Evaluation of liposomes Physical properties 1. Particle size: Both particle size and particle size distribution of liposomes influence their physical stability. These can be determined by the following method. a)Laser light scattering. b) Transmission electron microscopy.
  58. 58. 2. Surface charge • The positive, negative or neutral charge on the surface of the liposomes is due to the composition of the head groups. . The surface charge of liposomes governs the kinetic and extent of distribution in vivo, as well as interaction with the target cells. . The method involved in the measurement of surface charge is based on free-flow electrophoresis of MLVs.
  59. 59. Cont… • This technique can be used for determining the heterogeneity of charges in the liposome suspension as well as to detect any impurities such as fatty acids.
  60. 60. 3. Percent drug encapsulated • Quantity of drug entrapped in the liposomes helps to estimate the behavior of the drug in biological system. • Liposomes are mixture of encapsulated and unencapsulated drug fractions. • The % of drug encapsulation is done by first separating the free drug fraction from encapsulated drug fraction.
  61. 61. 4. Phase behavior • At transition temperature liposomes undergo reversible phase transition. • The transition temperature is the indication of stability permeability and also indicates the region of drug entrapment. • Done by DSC.
  62. 62. 5. Drug Release Rate . The rate of drug release from the liposomes can be determined by in vivo assays which helps to predict the pharmacokinetics and bioavailability of the drug. . However in vivo studies are found to be more complete.
  63. 63. Applications • Liposomes as drug or protein delivery vehicles. • Liposome in antimicrobial, antifungal(lung therapeutics) and antiviral (anti HIV) therapy. • In tumor therapy. • In gene therapy. • In immunology. • Liposomes as artificial blood surrogates. •
  64. 64. Lecture No. 1/References •Sovan Lal Pal, Utpal Jana, P. K. Manna, G. P. Mohanta, R. Manavalan, Nanoparticle: An overview of preparation and characterization, Journal of Applied Pharmaceutical Science 2011; 1:6: 228-234. •Gayatri Khosla, Lakshmi Goswami, Preeti Kothiyal, Sayantan Mukhopadhyay, Nanoparticles: A Novelistic Approach for CNS disorders, Journal of Advanced Pharmaceutical Sciences 2012; 2:2: 220-259. •Abhilash M., Potential applications of Nanoparticles, International Journal of Pharma and Bio Sciences 2010; 1:1: 1- 12.