Nanoparticles drug delivery system

Sr no Contents
1 Introduction
2 Advantages and disadvantages
3 Types of nanoparticle
4 Classification of Nanoparticle
5 Polymers used in nanoparticles
6 Method of preparation
7 Evaluation of nanoparticles
8 Application of nanoparticles
9 References
Nanoparticles is derived from the Greek word Nano means extremely small.
Nanoparticles are sub Nano sized colloidal drug delivery systems .
Particle size ranges from 10-1000 nm in diameter .
They are made up of natural, synthetic or semi synthetic polymers carrying drugs or proteinaceous substances, i.e. antigen(s) .
Drugs are entrapped either in the polymer matrix as a particulates or solid solutions or may be bound to particle surface by physical adsorption or by chemical reaction.
Drug can be added during preparation of nanoparticles or to the previously prepared nanoparticles
Nanoparticles can act as controlled release system depending on their polymeric composition.
As a targeted drug carrier nanoparticles reduce drug toxicity
Less amount of dose required.
They enhance aqueous solubility of poorly soluble drug therefore increase its bioavailability, therapeutic efficacy and Reduces side effects.
Nanoparticles can be administer by various routes including oral, nasal, parenteral, intra-ocular etc.
A) AMPHIPHILIC MACROMOLECULE CROSS-LINKING
B) Polymerization method
C)Polymer precipitation method

Heat cross-linking
Chemical cross-linking
Emulsion chemical dehydration
By Crosslinking in W/O Emulsion
PH-induced aggregation
Counter ion induced aggregation
Emulsion polymerization a)Micellar nucleation and polymerization b)Homogenous nucleation and polymerization)
Dispersion polymerization
Interfacial polymerization
Emulsion solvent evaporation method
Double emulsion and evaporation method
Solvent displacement
Salting out
Nanoprecipitation

1. Nanoparticles Presented by Siddique Adnan Rehmatullah FY Mpharm Guided by Dr Geeta Bhagawat. 1

2. Sr no Contents 1 Introduction 2 Advantages and disadvantages 3 Types of nanoparticle 4 Classification of Nanoparticle 5 Polymers used in nanoparticles 6 Method of preparation 7 Evaluation of nanoparticles 8 Application of nanoparticles 9 References 2

3. Introduction Nanoparticles is derived from the Greek word Nano means extremely small. Nanoparticles are sub Nano sized colloidal drug delivery systems . Particle size ranges from 10-1000 nm in diameter . They are made up of natural, synthetic or semi synthetic polymers carrying drugs or proteinaceous substances, i.e. antigen(s) . Drugs are entrapped either in the polymer matrix as a particulates or solid solutions or may be bound to particle surface by physical adsorption or by chemical reaction. Drug can be added during preparation of nanoparticles or to the previously prepared nanoparticles 3

4. Why Nanoparticles? Nanoparticles are intensively studied because of their possible effects on human health . They provide numerous benefits over the available conventional dosage forms They provide Greater surface area Provide Greater bio-availability Offer Less toxicity They are so tiny that their removal by Macrophages is avoided They are able to avoid renal filtration They can easily cross cell membranes Their interaction with cell surfaces are possible Targeted drug delivery to specific organ can be easily achieved. Provide good retention consequently less clearing & enhanced bioavailability. Most of the Nano formulations present biocompatibility with the living system 4

5. Advantages Nanoparticles can act as controlled release system depending on their polymeric composition. As a targeted drug carrier nanoparticles reduce drug toxicity Less amount of dose required. They enhance aqueous solubility of poorly soluble drug therefore increase its bioavailability , therapeutic efficacy and Reduces side effects. Nanoparticles can be administer by various routes including oral, nasal, parenteral , intra-ocular etc. 5

6. Disadvantages High cost Productivity more difficult Reduced ability to adjust the dose Highly sophisticated technology Requires skills to manufacture Difficult to maintain stability of dosage form. E.g .: Resealed erythrocytes stored at 40C. Susceptible to bursting and leakage of contents. 6

7. Types of Nanoparticles Nano spheres : Nano spheres are matrix systems in which the drug is physically and uniformly dispersed Nano capsules : Nano capsules are systems in which the drug is confined to a cavity surrounded by a unique polymer membrane. Figure No 1 Nano capsule and Nano sphere 7

8. Classification of nanoparticles 8

9. Polymers use in preparation of nanoparticles Natural polymers Synthetic polymers Proteins Polysaccharides Pre polymerised polymer Polymerised in process polymer Gelatin Albumin Lectins Legumin Alginate Dextran Chitosan Agarose Poly(e-caprolactone) Polylactic acid Poly(lactide-co-glycolide) Polystyrene Poly(isobutylcynoacrylate) Poly(butylcynoacrylate) Poly(hexylcynoacrylate) Polymethylmethacrylate Table No 1 Polymers use in preparation of nanoparticles 9

10. Size of nanoparticles required Inherent properties of the drug , ex. Aqueous solubility Surface characteristics such as charge and permeability Degree of biodegradability, biocompatibility and toxicity Drug release profile desired Antigenicity of the final product Factors affecting selection of material for preparation of nanoparticles 10

11. Method of preparation A) AMPHIPHILIC MACROMOLECULE CROSS-LINKING B) Polymerization method C)Polymer precipitation method Heat cross-linking Chemical cross-linking Emulsion chemical dehydration By Crosslinking in W/O Emulsion PH-induced aggregation Counter ion induced aggregation Emulsion polymerization a)Micellar nucleation and polymerization b)Homogenous nucleation and polymerization) Dispersion polymerization Interfacial polymerization Emulsion solvent evaporation method Double emulsion and evaporation method Solvent displacement Salting out Nanoprecipitation Table No 2 Method of preparation 11

12. A ) By Cross-linking of Amphiphilic macromolecules Nano particle can be prepared from amphiphlic macromolecules , proteins and polysaccharides this technique involves firstly the aggregation of amphiphile followed by further stabilization either by a)      Heat cross-linking b)      Chemical cross-linking This technique required a biphasic o/w or w/o type dispersed system which subdivides the amphilile prior to aggregative stabilization 12

13. 1 ) By heat denaturation or crosslinking Aqueous solution of protein + oily solution W/O EMULSION Now the w/o emulsion poured over preheated oil (heated upto 100 C and mainatined above 100 C temp and stirred Denaturation and aggregation of protein content of aqueous and to evaporate water Proteinaceous nanoparticle are formed 13

14. 2) By chemical cross linking agent Preparation of the aqueous solution of polymer (aluminium in water) Emulsified the solution of ethyl cellulose in chloroform and then cross linking is done by cross linking agent like glutaraldeheyde Stirring for several hour Nanospheres Wash with toulene Frezze dried Nano particle 14

15. 3 ) By emulsion chemical dehydration 15

16. 4)By Crosslinking in W/O Emulsion Mainly use for the entrapment of hydrophillic drug The method involves the emulsification of bovine serum albumin/human serum albumin or protein aq. solution in oil using high pressure homogenization or high frequency sonication The w/o emulsion so formed is poured into preheated oil. The suspension in preheated oil maintained above 100C is held stirred for specified time in order to denature & aggregate the protein contents of aq. pool completely & to evaporate water Protineaceous subnanoscopic particles are formed The particles are finally washed with organic solvent to remove any oil traces & collected by centrifugation The main factors are emulsification energy & temperature (used for denaturation & aggregation) 16

17. 4) By Crosslinking in W/O Emulsion continue.. Figure No 2 schematic of macromolecular cross-linking in a water in oil emulsion 17

18. 5 )By pH lnduced Aggregation This method of nanoparticle formation is mainly use for the proteins In this method change in pH gradient is used as driving force for making nanoparticles For example preparation of gelatin Nano spheres Gelatin & Tween 20 were dissolved in aqueous phase & pH was adjusted to optimum value. The clear Solutions obtained was heated at 40 o c ,then followed by quenching at 4 o C for 24h and then left at room temperature for 48 hr The sequential temperature changes leads to colloidal dispersion of aggregated gelatin. The aggregates were finally cross linked using glutaraldehyde. The ideal PH range is 5.5-6.5. for formation of nanosphere if below 5.5 no formation of Nano spheres while above 6.5 lead to formation of uncontrollably large Nano spheres 18

19. 6 ) Counter ion induced aggregation This another method which is used for the preparation of protein nanoparticles In this technique the principle involved is addition of the counter ion which induces Separation of protein phase from the aqueous medium. Then aggregation of dispersed phase can be initiated after addition of counter ions followed by rigidization step. For example preparation of aliginate nanoparticle using counter ion induced gelation technique where gelation was induced by calcium ion and continued by addition of poly (l-lysine) 19

20. B)Nanoparticle Preparation Using Polymerization Based Methods The polymers used in this are poly methyl methacrylate, polyacrylamide, polybutyl cyanoacrylate.,etc Two approaches adopted for preparation of nanoparticles using polymerization technique are:- Methods in which the monomer to be polymerized is emulsified in a non-solvent phase ( E mulsion polymerization ) Methods in which the monomer is dissolved in a solvent that is non solvent for the resulting polymer ( Dispersion polymerization ) In EP method the monomer is dissolved in an internal phase while in case of DP it is taken in dispersed phase In both cases after polymerization polymer tends to be insoluble in internal phase & dispersed phase results into suspension of Nano spheres. 20

21.   1)EMULSION POLYMERIZATION The process can be either :- Conventional – continuous phase is aqueous i.e . o/w emulsion Inverse – continuous phase is organic i.e.w/o emulsion . Two mechanisms of emulsion polymerization are Micellar nucleation and polymerization Homogenous nucleation and polymerization 21

22. 1A)Micellar nucleation and polymerization I nvolves swollen monomer micelles as the site of nucleation & polymerization . In this the monomer is emulsified in non-solvent phase using surfactant molecules This leads to the formation of 1 Monomer- swollen micelle 2 Stabilized monomer droplet 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 reactive monomers in continuous phase, which then collide with surrounding unrelative 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 . 22

23. 1A)Micellar nucleation polymerization continue… Figure No 4 Emulsion polymerization (Micellar polymerization mechanism) for nanoparticle preparation 23

24. 1B)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 entrapped to form nanoparticles. 24

25. Figure No 5 Emulsion polymerization (homogenous polymerization mechanism) for nanoparticle preparation 1B)Homogenous nucleation and polymerization continue… 25

26. 2)Dispersion polymerization In emulsion polymerization, monomer is emulsified in an immiscible phase (non-solvent) phase by means of surfactants. In case of dispersion polymerization, monomer is dissolved in aqueous medium which acts as precipitant for polymer. The monomer is introduced into the dispersion medium of an emulsion. Polymerization is initiated by adding a catalyst & proceeds with nucleation phase followed by growth phase. The nucleation is directly induced in aqueous monomer solution and presence of stabilizer or surfactant is not necessary for formulation of stable Nano spheres T his method is used to prepare biodegradable polyacrylamide and polymethyl-methacrylate (PMMA) nanoparticles . Being very slowly biodegradable and biocompatible, PMMA nanoparticles have been considered as optimal polymeric systems for vaccination purpose. 26

27. Figure No 6 Dispersion polymerization mechanism for nanoparticle preparation 2)Dispersion polymerization continue… 27

28. 3)  INTERFACIAL POLYMERIZATION In this method preformed polymer phase is used which is finally transformed into an embryonic sheath A polymer that will eventually become a core of nanoparticle and drug which is to be loaded is dissolved in volatile solvent The solution is then poured into a non solvent for both polymer and core phase The polymer phase is separated as a coacervate phase at O/W interface The resultant mixture instantaneously turns milky owing to the formation of nanoparticle For example interfacial polymeric condensation of 2,2-bis-(4 hydroxyphenyl)propane and sebacoyl chloride. 28

29. 3) INTERFACIAL POLYMERIZATION Continue …. Figure No 7 preparation of nanocapusle using interfacial polymer condesation Figure No 8 Interfacial polymerization 29

30. C)Polymer Precipitation Methods: In these methods, the hydrophobic polymer and/or a hydrophobic drug is dissolved in a particular organic solvent followed by its dispersion in a continuous aqueous phase, in which the polymer is insoluble. The external phase also contains the stabilizer. Depending upon solvent miscibility techniques they are designated as solvent extraction/evaporation The polymer precipitation occurs as a consequence of the solvent extraction or evaporation, which can be brought about by: Increasing the solubility of the organic solvent in the external medium by adding an alcohol(i.e., isopropanol) By incorporating additional amount of water into the ultraemulsion (to extract or diffuse the solvent) By evaporation of the organic solvent at room temperature or at accelerated temperatures or by using vacuum Using an organic solvent that is completely soluble in the continuous aqueous phase (i.e., acetone) Nano precipitation 30

31. They are 5 types Emulsion Solvent evaporation method Double emulsion and solvent evaporation method. Solvent Displacement / Precipitation method. Salting out. Nano precipitation. Polymer Precipitation Methods: 31

32. 1)Emulsion solvent evaporation method Polymer and drug is dissolved in an organic solvent such as dichloromethane, chloroform or ethyl acetate. The mixture of polymer and drug solution is then emulsified in an aqueous solution containing a surfactant or emulsifying agent to form an oil in water ( o/w) emulsion. After the formation of stable emulsion, the organic solvent is evaporated either by reducing the pressure or by continuous stirring. Nanoparticles 32

33. 1)Emulsion solvent evaporation method continue… Figure No 9 nanoparticle preparation using emulsion solvent evaporation method 33

34. 2)Double emulsion solvent evaporation method The emulsion and evaporation method suffer from the limitation of poor entrapment of hydrophilic drugs . Therefore to encapsulate hydrophilic drug the double emulsion technique is employed, which involves the addition of aqueous drug solutions to organic polymer solution under vigorous stirring to form w/o emulsions. This w/o emulsion is added into second aqueous phase with continuous stirring to form the w/o/w emulsion. The emulsion then subjected to solvent removal by evaporation and Nano particles can be isolated by centrifugation at high speed . 34

35. 2)Double emulsion solvent evaporation method continue… Figure No 10 nanoparticle preparation using double emulsion solvent evaporation method 35

36. 3)Solvent Displacement / Precipitation method It is based on interfacial deposition of a polymer following displacement of a semi polar solvent miscible with water from a lipophilic solution It involve the use of an organic phase which is completely soluble in external aqueous phase The organic solvent diffuses instantaneously to the external aqueous. Phase inducing immediate polymer precipitation because of complete miscibility of both the phases This method is particularly useful for drugs that are slightly soluble in water. 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 36

37. 3)Solvent Displacement / Precipitation method continue…. Figure No 11 solvent displacement method to prepare nanoparticles ( conventional Method) and nanocapusle (modified method) 37

38. 4)Salting out method 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 ). This oil/water 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 Nano spheres. This method is suitable for drugs & polymers that are soluble in polar solvents such as acetone & ethanol 38

39. Figure No 12 nanoparticle preparation by salting out method 4)Salting out method continue…. 39

40. 5 ) Nanoprecipitation Polymers, drug, and or lipophilic surfactant are dissolved in a water miscible solvent such as acetone or ethanol . The solution is then poured or injected into an aqueous solution containing stabilizer under magnetic stirring. Nano particles are formed instantaneously by the rapid solvent diffusion(Polymer deposition on the interface between the water and the organic solvent, caused by fast diffusion of the solvent) Nanoparticles were separated by using cooling centrifuge 40

41. This method is useful for drugs that are slightly soluble in water. If the drug is highly hydrophilic, it diffuses out into external aqueous phase as nanocrystals , which further grow during storage 5)Nanoprecipitation Figure No 12 nanoparticle preparation by nanoprecipitation method 41

42. Technique Candidate drug Polymer used Heat denaturation and cross linking in w/o emulsion Hydrophilic Hydrophilic Albumin ,Gelatin Emulsion polymerization Hydrophilic Hydrophobic Poly(alkylcyanoacrylate) Solvent extraction evaporation Hydrophilic and Hydrophobic Soluble in polar solvent Polyesters Poly (lactic acid), poly( caprolactone) Salting out Soluble in polar solvent Polyesters Poly (lactic acid), Poly (lactide-co-glycolide) Polymer used for the preparation of nanoparticle 42 Table No 3 polymer used for preparation of nanoparticles

43. Polymer used for the preparation of nanoparticle continue… Technique Candidate drug Polymer used Solvent displacement Hydrophilic and Hydrophobic Soluble in polar solvent Polyesters Poly (lactic acid), Poly (lactide-co-glycolide) Interfacial O/W polymerization Hydrophobic Hydrophobic Poly(alkylcyanoacrylate) Desolvation and cross linking in water Hydrophilic and protein affinity Hydrophilic Albumin ,Gelatin Cross-linking in water Hydrophilic and protein affinity Hydrophilic Alginates and chitosan 43 Table No 3 polymer used for preparation of nanoparticles

44. Evaluation of nanoparticles: Parameter Characterization method Particle size & size distribution Photon correlation spectroscopy(PCS) Laser defractometry TEM SEM Atomic force microscopy Surface charge Laser Doppler Anemometry Zeta potentiometer Shape and surface morphology TEM SEM Atomic force microscopy 44 Table No 4 Evaluation of nanoparticles

45. Parameter Characterization method Dru g Nanoparticle recovery and drug incorporation efficiency Entrapment Efficiency Drug loading Surface Hydrophobicity Water contact angle measurement Rose Bengal(dye) binding X-ray photoelectron spectroscopy Carrier Drug interactions and Physical state characterization Diffential scanning calorimetry FTIR Xray diffraction studies In vitro drug release studies Reverse dialysis bag technique Dialysis bag diffusion technique. centrifugal ultra-filtration techniques Evaluation of nanoparticles: 45 Table No 4 Evaluation of nanoparticles

46. Particle size & size distribution P article size & their distribution are the important parameters which need to be studied carefully as most of the properties of nanoparticle used for drug delivery depend on it. The methodologies, commonly followed are: Photon correlation spectroscopy Laser diffractometry TEM (Transmission Electron Microscopy) SEM (Scanning Electron Microscopy) Atomic force microscopy (AFM) Mercury prositometry 46

47. Surface charge The charge on the nanoparticle formulation is also important parameter which should be studied as it is only the charge which will decide the interaction of nanoparticle with the biological surface. Nanoparticles also show the charge dependent accumulation in different body organs Also , the surface charge on nanoparticle is determinant of aggregation of particles. The techniques used for measuring surface charge are: Laser Doppler Anemometry: it works on the laser scattering principle Zeta Potentiometer: Basic principle is electrophoretic mobility 47

48. Shape and surface morphology S hape of nanoparticles is a very crucial parameter as various studies have demonstrated the shape dependent distribution of NPs in animal. Shape and surface morphology of NPs can be determined by the following techniques Transmittance electron microscope (TEM) Scanning electron microscope Atomic force microscopy 48

49. Nanoparticle recovery and drug incorporation efficiency Entrapment efficiency: It is calculated with respect to the initial amount of drug added during the formulation development. It can be determined by direct/indirect method using the following formula ; Drug loading: It is calculated with respect the formulation i.e. amount of the drug present in the final formulation . It can be determined by direct/indirect using the following formula; 49

50. Surface Hydrophobicity Hydrophobicity of nanoparticles influences the interaction of nanoparticle with the biological system & ultimately influences the bio fate. Surface Hydrophobicity of nanoparticles is measured by: Water Contact Angle Measurement Dye Binding (Rose Bengal) Hydrophobic Interaction Chromatography X-Ray Photo Electron Microscopy 50

51. Carrier Drug interactions and Physical state characterization Diffential scanning calorimetry :- It is preliminary technique for the identification of any possible interaction between formulation components. Thermograms of each constituent of the formulations are recorded & compared with that of the final formulation; appearance of any extra peak or disappearance of existing peak shows the interaction among the components FTIR :- It is a confirmatory analytical tool to define the interaction between formulation components. FTIR spectra of each constituent of the formulations are recorded & compared with that of the final formulation ; appearance of any extra peak or disappearance of existing peak shows the interaction among the components Xray diffraction studies :- Powder X-ray diffraction may be readily used to determine the crystal structure of simple lattice structures . In this technique diffraction of X-rays, at a specific range of angle, is observed 51

52. In vitro d rug release studies It is necessary to determine the release pattern of the nanoparticle formulations whether they are releasing the drug in the desired manner. A number of methods can be used to determine in vitro release of drug Reverse dialysis bag technique Dialysis bag diffusion technique. C entrifugal ultra-filtration techniques Using biological or artificial membrane i.e. Side-by-side diffusion of cells. 52

53. Application of nanoparticles Application Material Purpose Cancer therapy Poly(alkylcyanoacrylate) nanoparticle with anticancer agents, oligonucleotides Targeting , reduced toxicity, enhanced uptake of antitumour agents, improved in vivo & in vitro stability Peroral absorption Poly(methylmethacrylate)nanoparticles with proteins & therapeutic agents Enhanced bioavailability &protection from GI enzymes Ocular delivery DNA gelatin nanoparticles, DNA chitosan nanoparticles, Enhanced delivery & higher expression levels 53 Table No 5 Application of nanoparticles

54. Application Material Purpose Oligonucleotide delivery Alginate nanoparticles, poly(D,L)lactic acid nanoparticles Enhanced delivery of oligonucleotide Prolonged systemic circulation Polyesters with adsorbed polyethylene glycols or pluronics Prolong systemic drug effect,avoid uptake by RES Intracellular targeting Poly(alkylcyanoacrylate) Polyester nanoparticles with anti parasitic or antiviral agents Target RES for intracellular interactions Application of nanoparticles 54 Table No 5 Application of nanoparticles

55. Reference Targetted and controlled drug delivery by S.P. VYAS and R.K. KHAR JAPS Nanoparticle: An overview of preparation and Characterization BY Sovan Lal Pal, Utpal Jana, P. K. Manna, G. P. Mohanta, R. Manavalan Pelagia Research Library Formulation, Characterization and Application on Nanoparticle : A Review Abhishek Garg*, Sharad Visht, Nitin Kumar Tropical Journal of Pharmaceutical Research, June 2006; 5 (1): 561-573Nanoparticles – A Review VJ Mohanraj* and Y Chen Jain N.K. “Advances in controlled and novel Drug Delivery”, CBS publisher & Distributers, Edition 1st 2001, Pg. 408 Nanotechnology in drug delivery - A Review, Indian Drugs, Issue 11,november 2011. 55

56. 56 Thank you