Nanoparticles, types, preparation and evaluation ppt.pptx

This ppt consists of information related to nanoparticles, their types and preparation and evaluation. it also consists of questions from the previous years exams conducted by RGUHS (Karnataka) university. Targeted drug delivery.

1. INTRODUCTION PREPARATION & EVALUATION OF NANOPARTICLES PRESENTED BY: J Manjunath M Pharm 2 nd Semester DEPT. OF PHARMACEUTICS AACP 1 Presented To : Mrs. Tanushree Chakraborty Asso. Professor DEPT. OF PHARMACEUTICS AACP J Manjunath

2. WHAT ARE NANOPARTICLES? Nano derives from the Greek word “Nanos” which means Dwarf or Extremely small. It can be used as a prefix for any unit to mean a billionth of that unit. A nanometer is a billionth of a meter. 2 J Manjunath

3. DEFINITION : Nanoparticles are solid colloidal particles ranging from 1to100nm in size. They are composed of synthetic or semi synthetic polymers carrying drugs or proteinaceous substances, i.e. antigen(s). Drugs are entrapped, or encapsulated in the polymer matrix particulates or solid solutions or may be bound to particle surface by physical adsorption or in chemical form. 3 J Manjunath

4. The basic Concept involved is : Selective and Effective Localization of pharmacologically active moiety at pre selected target(s) in therapeutic concentration,, Provided restriction to access the tissues and cells. Nanoparticles are mainly taken by : Reticuloendothelial System (RES), after the administration. CONCEPT: 4 J Manjunath

5. Hence are useful to carry drugs to the liver and to cells that are phagocytically active. By modifying the surface characteristics of the nanoparticles it is possible to enhance the delivery of drugs to spleen relative to the liver. Distribution of the nanoparticles in the body may be achieved possibly by : Coating of nanoparticles with certain Serum components, Attachment of antibodies or sulfoxide groups and the use of Magnetic nanoparticles. 5 J Manjunath

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7. The term nanoparticle is a combined name for both nanospheres and nanocapsules. 7 J Manjunath

8. Nanospheres and Nanocapsules 8 J Manjunath

9.  Solid Lipid Nanoparticles  Polymeric Nanoparticles  Ceramic Nanoparticles  Hydrogel Nanoparticles  Copolymerized Peptide Nanoparticles  Nanocrystals and Nanosuspensions  Nanotubes And Nanowires  Functionalized Nanocarriers  Nanospheres  Nanocapsules DIFFERENT TYPES OF NANOPARTICLES 9 J Manjunath

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11.  Solid lipid Nanoparticles:  New type of colloidal drug carrier system for i.v. Consists of spherical solid lipid particles in the nm range, dispersed in water or in aqueous surfactant solution . Main reason for their development is the combination of advantages from different carriers systems like liposomes and polymeric anoparticles .  Polymeric nanoparticles (PNPs) :  They are defined as particulate dispersions or solid particles with size in the range of 10-1000nm.Composed of synthetic or semi-synthetic Polymers.  Biodegradable polymeric nanoparticles Polylactic acid (PLA), polyglycolic acid (PGA), Polylactic - glycolic acid (PLGA), and Polymethyl methacrylate (PMMA) Phospholipids Hydrophobic core. 11 J Manjunath

12.  Ceramic Nanoparticles: These are the nanoparticles made up of inorganic (ceramic) compounds silica, ( Inorganic/metal) titania and alumina. Exist in size less than 50 nm, which helps them in evading deeper parts of the body.  Hydrogel nanoparticles: Polymeric system involving the self-assembly and self aggregation of natural polymer amphiphilic cholesteryl pullulan , cholesteryl dextran and agarose cholesterol groups provide cross linking points. 12 J Manjunath

13.  Copolymerized Peptide Nanoparticles : Drug moiety is covalently bound to the carrier instead of being physically entrapped.  Nanocrystals And Nanosuspensions: Pure drug coated with surfactant, Aggregation of these particles in crystalline form. Drug powder dispersed in aqueous surfactant solution.  Functionalized Nanocarriers: Biological materials like proteins, enzymes, peptides etc… are being utilized as a carriers for the drug delivery. 13 J Manjunath

14. Advantages of nanoparticles • Nanoparticles can be administered by various routes including oral, nasal, parenteral, intra-ocular etc. • Due to small particle size nanoparticles overcome resistance by physiological barriers in the body and easily penetrates to cell walls, blood vessels, stomach epithelium and blood–brain barrier. • As a targeted drug carrier nanoparticles reduce drug toxicity and enhance efficient drug distribution • Polymeric nanoparticle an ideal drug delivery system for cancer therapy, vaccines, contraceptives and antibiotics. • Useful to diagnose various diseases • Enhanced stability of ingredients • Prolonged shelf life • Used in dental surgery also as filling the tiny holes in teeth. 14 J Manjunath

15. Disadvantages Of Nanoparticles • Small size & large surface area can lead to particle aggregation. • Physical handling of nano particles is difficult in liquid and dry forms. • Limited drug loading. • Toxic metabolites may form. • Difficult to maintain stability of dosage form. E.g : Resealed erythrocytes stored at 4 C. 15 J Manjunath

16. » It should be biochemically inert , non toxic and non-immunogenic. » It should be stable both physically and chemically in in-vivo & in-vitro conditions. » Restrict drug distribution to non-target cells or tissues or organs & should have uniform distribution. » Controllable & Predictable rate of drug release. IDEAL CHARACTERISTICS » Drug release should not effect drug action » Specific Therapeutic amount of drug release must be possessed » Carriers used must be biodegradable or readily eliminated from the body without any problem and no carrier induced modulation in disease state. » The preparation of the delivery system should be easy or reasonable » Simple, reproducible & cost effective. 16 J Manjunath

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19. A : Amphiphilic Macromolecules Cross Linking Methods 1) Crosslinking in W/O Emulsion 2) Emulsion chemical dehydration 3) Phase Separation in Aqueous Medium (Desolvation) 4) pH induced Aggregation B : Polymerization Methods 1) Emulsion polymerization 2) Dispersion polymerization 3) Interfacial condensation polymerization 4) Interfacial complexation C : Polymer precipitation methods 1) Solvent evaporation/extraction 2) Solvent displacement (nanoprecipitation) 3) Salting out METHODS OF PREPARATION 19 J Manjunath

20. AMPHIPHILIC MACROMOLECULES CROSS LINKING METHODS Nanoparticles can be prepared from Amphiphilic macromolecules, proteins and polysaccharides (which have affinity for aqueous and lipid solvents). The method involves Aggregation of Amphiphiles followed by stabilization either by heat denaturation or chemical cross-linking. These processes may occur in a biphasic O/W or W/O type dispersed systems, which subdivide the amphiphile(s) prior to aggregative stabilization. It may also take place in an aqueous amphiphilic solution where on removal, extraction, or diffusion of solvent, amphiphiles are aggregated as tiny particulates & subsequently rigidized via chemical cross-linking. 20 J Manjunath

21. Cross linking in W/O Emulsion The cross linking method is exhaustively used for the nano -encapsulation of drugs The method involves the emulsification of bovine serum albumin (BSA) or human serum albumin (HSA) or protein aqueous solution in oil using high-pressure homogenization or high frequency sonication. The W/O emulsion so formed is then poured into preheated oil (temp. above 100 C), which is then stirred for a specified time in order to denature & aggregate the protein contents of aqueous pool completely & to evaporate the water. Proteinaceous sub-nanoscopic particles are thus formed where the size of internal phase globules mainly determines the ultimate size of particulates. The particles are finally washed with an organic solvent to remove any adherent or adsorbed oil traces & subsequently collected by centrifugation. The crucial factors which governs the size & shape of nanoparticles are mainly emulsification energy & temperature (used for denaturation & aggregation). 21 J Manjunath

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23. 2) Emulsion Chemical Dehydration » Stabilization can also be achieved by emulsion chemical dehydration. » Hydroxy propyl cellulose solution in chloroform is used as a continuous phase, & » A chemical dehydrating agent, 2,2, di-methyl propane is used to disperse into the internal aqueous phase to form an Emulsion. » ADV : The method avoid coalescence of droplets and could produce nanoparticles of smaller size (300nm). 3) Phase Separation in Aqueous Medium (Desolvation ) » The protein or polysaccharide from an aqueous phase can be Desolvated by : ˃ A) pH change ˃ B) Change in temperature ˃ C) Addition of appropriate counter ions e.g. alginate 23 J Manjunath

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25. Gelatin Nanospheres were prepared by : Gelatin & tween 20 were dissolved in aq. phase & pH of the solution was adjusted to optimum value. The clear solution so obtained was heated to 40 C followed by its quenching at 4 C for 24hrs & subsequently left at ambient temperature for 48hrs. The sequential temperature treatment resulted into a colloidal dispersion of aggregated gelatin. The aggregates were finally cross linked using glutaraldehyde as cross linking agent. The nanospheres thus resulted were of 200 nm average size with uniform dispersity. The optimum pH range for ideal & uniform preparation of gelatin nanospheres was 5.5- 6.5. pH value below 5.5 produced no aggregation while above 6.5 an uncontrolled aggregation led to the formation of larger nanospheres 4) pH Induced Aggregation 25 J Manjunath

26. B . POLYMERIZATION BASED METHODS The polymers used for nanosphere preparation include; Poly(methylmethacrylate) Poly(butyl cyano-acrylate) Poly(acrylamide) N-N’methylene-bis-acrylamide 1) Emulsion Polymerization Emulsion Polymerization is a method in which the monomer to be polymerized is emulsified in a non-solvent phase. The process can be conventional or inverse, depending upon the nature of the continuous phase in the emulsion. In Conventional, the continuous phase is aqueous (O/W) In Inverse, the continuous phase is organic (W/O) Two different mechanisms were proposed for the emulsion polymerization process Micellar nucleation & polymerization Homogenous nucleation & polymerization 26 J Manjunath

27. a) Micellar nucleation and polymerization In this the monomer is emulsified in non-solvent phase using surfactant molecules. This leads to the formation of Monomer- swollen micelle & Stabilized monomer droplets. Monomer-swollen micelle have sizes in nanometric range and have much larger surface area compared to monomer droplet Polymerization reaction proceeds through nucleation and propagation stage in presence of chemical or physical initiator. Energy provided by initiator creates free monomers in continuous phase, which then collide with surrounding unreactive monomers and initiate polymerization chain reaction. The monomer molecule reaches the micelle by diffusion from the monomer droplets through continuous phase, thus allowing polymerization to progress within micelles. Here monomer droplets act as reservoirs of monomers. 27 J Manjunath

28. As monomer is slightly soluble in surrounding phase, it diffuses from monomer droplets and reach monomer micelles through continuous phase. Thus polymerization takes places in MICELLES. 28 J Manjunath

29. b) Homogenous nucleation and polymerization In this method monomer is sufficiently soluble in continuous outer phase. Nucleation and polymerization can directly occur in this phase leading to formation of primary chains called oligomers. In this both micelle and droplets act as monomers reservoir throughout polymer chain length. When oligomers reach certain length, they precipitate and form primary particles and stabilized by surfactant molecules provided by micelle and droplets in which the drug will be entrapped to form nanoparticles. The polymerization rate is dependent on the pH of the medium. Anionic polymerization takes place in micelle after diffusion of monomer molecules through the water phase and is initiated by negative charged compound At neutral pH the rate of polymerization is extremely fast. 29 J Manjunath

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31. Nucleation is directly induced in aqueous monomer solution and presence of stabilizer or surfactant is not necessary for the formation of stable nanospheres. 2) Dispersion Polymerization In emulsion polymerization monomer is emulsified in an immiscible phase using surfactant. In case of dispersion polymerization monomer is dissolved in an aqueous medium which acts as precipitant for polymer The monomer is introduced into the dispersion medium. Polymerization is initiated by adding a catalyst & proceeds with nucleation phase followed by growth phase. 31 J Manjunath

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33. 3) Interfacial polymerization The preformed polymer phase is finally transformed to an embryonic sheath. The polymer & drug are dissolved in a volatile solvent. The solution is poured into a non solvent for both polymer & core phase. The polymer phase is separated as a coacervate phase at o/w interface. The mixture turns milky due to formation of nanocapsules. This method is used for proteins, enzymes, antibodies, & cells The size of nanocapsules ranges from 30-300nm 33 J Manjunath

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35.  The method is based on the process of microencapsulation introduced by Lin & Sun 1969.  In case of nanoparticles preparation, aqueous polyelectrolyte solution is carefully dissolved in reverse micelles in an apolar bulk phase with the help of an appropriate surfactant.  Subsequently , competing polyelectrolyte is added to the bulk, which allows a layer of insoluble polyelectrolyte complex to coacervate at the interface. 4 ) Interfacial Complexation 35 J Manjunath

36. C . POLYMER PRECIPITATION METHODS The polymer precipitation is done by Increasing the solubility of organic solvent in the external medium by adding an alcohol (isopropanol) By incorporating water into ultra emulsion(to extract solvent) By evaporation of solvent at room temp. by using vacuum Using an organic solvent which is completely soluble in the continuous aq. phase(acetone)nanoprecipitation 36 J Manjunath

37. SOLVENT EVAPORATION METHOD Nanoparticles preparation using Emulsion solvent evaporation method This method involves the formation of a conventional O/W emulsion between a partially water miscible solvent containing the stabilizer. Ex: PLGA nanospheres The polymer is solubilized in a solvent (chloroform) and dispersed in gelatin solution by sonication to yield O/W emulsion. The solvent is eliminated by evaporation. For evaporation homogenizer is used which breaks the initial coarse emulsion in nanodroplets yielding nanospheres. 37 J Manjunath

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40. 2) SOLVENT DISPLACEMENT METHOD (Nanoprecipitation) It is based on interfacial deposition of a polymer following displacement of a semi polar solvent miscible with water from a lipophilic solution The organic solvent diffuses instantaneously to the external aq. Phase inducing immediate polymer precipitation because of complete miscibility of both the phases If drug is highly hydrophilic it diffuses out into the external aq. phase while if drug is hydrophobic it precipitates in aq. medium as nanocrystals 40 J Manjunath

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42. 3) SALTING OUT TECHNIQUE • Salting out is based on the separation of a water-miscible solvent from aqueous solution via a salting-out effect. • Polymer and drug are initially dissolved in a solvent which is subsequently emulsified into an aqueous gel containing the salting out agent (electrolytes, such as magnesium chloride and calcium chloride, or non- electrolytes such as sucrose) and a colloidal stabilizer such as polyvinylpyrrolidone (PVP) or hydroxyethylcellulose. This O/W emulsion is diluted with a sufficient volume of water or aqueous solution to enhance the diffusion of solvent into the aqueous phase, thus inducing the formation of nanospheres. It is different from nanoprecipitation method as in nanoprecipitation polymeric solution is completely miscible with the external phase. But in this method the miscibility of both the phase is prevented by the saturation of external aqueous phase with PVA and Magnesium chloride. 42 J Manjunath

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44. NOVEL NANOPARTICULATE SYSTEMS Solid Lipid Nanoparticles: These are sub-micron colloidal carriers (50-100nm) which are composed of physiological lipid dispersed in water or in a aqueous surfactant solution.  Micro emulsion technique was used for the production of solid lipid nanoparticles  Homogenization method at higher pressure for either melted or solid lipids has been suggested to obtain SLN. 44 J Manjunath

45. Small size and relatively narrow size distribution which provide biological opportunities for site specific drug delivery by SLNs. Controlled release of active drug over a long period can be achieved Protection of incorporated drug against chemical degradation. No toxic metabolites are produced Relatively cheaper and stable. Ease of industrial scale production by hot dispersion technique. Advantages of SLN 45 J Manjunath

46. Hot Homogenization Technique:  Homogenization of melted lipids at elevated temperature. Cold Homogenization Technique :  Homogenization of a suspension of solid lipid at room temperature. Preparation Methods of SLN 46 J Manjunath

47. Hot Homogenization Technique Melting of the lipid Dissolution of drug in melted lipid Mixing of preheated dispersion medium & drug lipid melt Premix using stirrer to form coarse pre-emulsion High pressure homogenization at a temp. above the lipids melting point o/w nanoemulsion Solidification of the nanoemulsion by cooling down to room temp. to form SLN 47 J Manjunath

48. Cold Homogenization Technique Melting of the lipid Dissolution /solubilization of drug in melted lipid Solidification of drug loaded lipid in liquid nitrogen or dry ice Grinding in a powder mill(50-100μm particles) Dispersion of lipid in the cold aqueous dispersion medium Solid lipid nanoparticles 48 J Manjunath

49.  Nanocrystals and Nanosuspensions are two recently introduced aspects to drug delivery research.  The basic theme is to convert micronized drug powders to drug nanoparticles. NANOCRYSTALS & NANOSUSPENSIONS 49 J Manjunath

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51. PHARMACEUTICAL ASPECTS OF NANOPARTICLES  Should be free from potential toxic impurities  Should be easy to store and administer  Should be sterile if parenteral use is advocated. Three important process parameters are performed before releasing them for clinical trials: o Purification o Freeze drying o Sterilization. 51 J Manjunath

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55.  This method has been suggested for the purification of nanoparticles and the method can be scaled up from an industrial stand point.  In this method the suspension is filtered through membranes with direction of fluid being tangential to surface of membrane.  Depending on the type of membrane used either microfiltration or ultra filtration can be performed. Cross-flow filtration technique 55 J Manjunath

56. Freeze drying of nanoparticles It includes freezing of nanoparticle suspension & sublimation of water to produce free flowing powder. Advantages are Prevention from degradation & or solubilization of the polymer Prevention from drug leakage, drug desorption, drug degradation Nanocapsules containing oily core may be processed in the presence of mono or disaccharides (glucose or sucrose) Readily dispersible in water without modifications in their physicochemical properties 56 J Manjunath

57. Sterilization of Nanoparticles Nanoparticles intended for parenteral use should be sterilized to be pyrogen free before animal or human use. Sterilization in nanoparticles is achieved by using aseptic technique throughout their preparation & processing & formulation & by sterilizing treatments like autoclaving or γ- irradiation 57 J Manjunath

58. CHARACTERIZATION OF NANOPARTICLES PARAMETER CHARACTERIZATION METHOD Particle size & size distribution Photon correlation spectroscopy, Laser defractometry, Transmission electron microscopy, SEM, Atomic force microscopy, Mercury porosimetry Charge determination Laser doppler anemometry, Zeta potentiometer Surface hydrophobicity Water contact angle measurements, Rose Bengal (dye) binding X-ray photoelectron spectroscopy Chemical analysis of surface Static secondary ion mass spectrometry, sorptometer Carrier-drug interaction Differential scanning calorimetry Nanoparticle dispersion stability Critical flocculation temp (CFT) Release profile In vitro release characteristics under physiologic & sink conditions Drug stability Bioassay of drug extracted from nanoparticles Chemical analysis of drug 58 J Manjunath

59. Evaluation parameter of Nanoparticles 1. Particle size 2. Density 3. Molecular weight 4. Structure and crystallinity 5. Specific surface area 6. Surface charge & electronic mobility 7. Surface hydrophobicity 8. In-vitro release 9. Nanoparticle yield 10. Drug entrapment efficiency 59 J Manjunath

60. 1.PARTICLE SIZE : • Photon correlation spectroscopy (PCS) : For smaller particle. • Laser diffractrometry : For larger particle. • Electron microscopy (EM ) : Required coating of conductive material such as gold & limited to dry sample. • Transmission electron microscopy (TEM) : Easier method & Permits differntiation among nanocapsule & nanoparticle. • Atomic force microscope Laser force microscope Scanning electron microscope 60 J Manjunath

61. 2.DENSITY : • Helium or air using a gas pycnometer • Density gradient centrifugation 3. MOLECULAR WEIGHT : • Gel permeation chromatography using refractive index detector. 4. STRUCTURE & CRYSTALLINITY : • X-ray diffraction • Thermoanalytical method such as, 1) Differential scanning calorimetry 2) Differential thermal analysis 3) Thermogravimetry 61 J Manjunath

62. 5. SPECIFIC SURFACE AREA : • Sorptometer Specific Surface Area, A = 6 / ρ .d Where, ρ is the density & d is the diameter of the particle 6. SURFACE CHARGE & ELECTRONIC MOBILITY : • Surface charge of particle can be determined by measuring particle velocity in electrical field. • Laser Doppler Anemometry tech. for determination of Nanoparticles velocities. • Surface charge is also measured as electrical mobility. • Charged composition critically decides biodistribution of nanoparticle . • Zeta potential can also be obtained by measuring the electronic mobility. 62 J Manjunath

63. 7. SURFACE HYDROPHOBICITY : • Important influence on interaction of nanoparticles with biological environment. • Several methods have been used, 1 Hydrophobic interaction chromatography. 2 Two phase partition. 3 Contact angle measurement. 8. INVITRO RELEASE : • Diffusion cell Recently introduce modified Ultra-filtration tech. • Media used : phosphate buffer 63 J Manjunath

64. 8. YIELD OF NANO PARTICLE : 9.DRUG ENTRAPMENT EFFICIENCY: The yield of nanoparticles was determined by comparing the whole weight of nanoparticles formed against the combined weight of the copolymer and drug. The nanoparticles were separated from the aqueous medium by ultracentrifugation at 10,000 rpm for 30 min. Then the resulting supernatant solution was decanted and dispersed into phosphate buffer saline pH 7.4. 64 J Manjunath

65. The amount of drug in supernatant was then subtracted from the total amount of drug added during preparation of nanoparticle (W). The amount of drug present in clear supernatant after centrifugation for 30 min at 10,000 rpm was determined by UV spectroscopy. 65 J Manjunath

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68. QUESTIONS : Discuss about Nanoparticles. (5M) Discuss the development of Nanoparticles for drug targeting. How are, they evaluated? (20M) Write a short note on Nanoparticles. (5M) List out the methods to prepare nanoparticles & explain any one method. (5M) State briefly on targeted drug delivery system with special reference to nanoparticles 68 J Manjunath

69. REFERENCES : Vyas S.P. , Khar R.K. Targeted & Controlled Drug Delivery, Novel Carrier Systems, CBS Publication,2002, Page No.331-386. Google.com(images) Jain N. K., Controlled and novel Drug Delivery, 1st edition 2001, CBS Publication; 292 - 301. 69 J Manjunath

70. THANK YOU 70 J Manjunath