Niosomes ppt class
- 1. Presented by Rohan Aggarwal (M Pharm sem II ) 05/MPH/DIPSAR/18 Department of Pharmaceutics A seminar on NIOSOMES
- 2. • Introduction • Advantages • Disadvantages • Structure of niosomes • Types of niosomes • Comparision between liposomes & niosomes • Composition of niosomes • Factors affecting properties of niosomes • Methods of Preparation • Evaluation of niosomes • Applications of niosomes • Marketed preparations Contents
- 3. • Niosomes are a novel drug delivery system, in which the medication is encapsulated in a vesicle composed of a bilayer of non-ionic surface active agents . • Niosomes are formed mostly by cholesterol incorporation as an excipient. • They are structurally similar to liposomes in having a bilayer, however, the materials used to prepare niosomes make them more stable and thus niosomes offer many more advantages over liposomes. • The particle size ranges from 10 nm-3000 nm. Introduction
- 4. Used for a variety of drugs : includes hydrophilic, lipophilic as well as amphiphilic moieties. Act as a depot to release the drug slowly and offer a controlled release. Osmotically active and stable. Increase the stability of the entrapped drug. Handling and storage of surfactants do not require any special conditions. Enhance the skin penetration of drugs. Advantages
- 5. Disadvantages • Physical Instability. • Aggregation. • Fusion. • Leaking of entrapped drug. • Hydrolysis of entrapped drug which limits the shelf life of the dispersion.
- 6. Niosomes are microscopic lamellar structures, which are formed on the admixture of non-ionic surfactant of the alkyl or dialkyl polyglycerol ether class and cholesterol with subsequent hydration in aqueous media. Niosomes may be unilamellar or multilamellar depending on the method used to prepare them. The hydrophilic ends are exposed on the outside and inside of the vesicle, while the hydrophobic chains face each other within the bilayer. Hence, the vesicle holds hydrophilic drugs within the space enclosed in the vesicle, while hydrophobic drugs are embedded within the bilayer itself. Structure
- 7. Figure 1: Structure of Niosomes
- 8. Small Unilamellar Vesicle (SUV) Large Unilamellar Vesicle (LUV) Multilamellar Vesicle (MLV) Typical Size Ranges: SLV: 10-100 nm LUV: 100-3000nm MLV: >3000 nm Types
- 10. COMPOSITION The major components used for the preparation of niosomes are : - Cholesterol - Nonionic surfactants - Charged groups 1.Cholesterol • Cholesterol is used to provide rigidity and proper shape, conformation to the niosomes preparations. • In the bilayer structure of niosomes, cholesterol forms hydrogen bonds with hydrophilic head of a surfactant.
- 11. 2. Nonionic surfactants • The role surfactants play a major role in the formation of niosomes. • Nonionic surfactants are amphiphilic molecules that comprise two different regions: one of them is hydrophilic (water-soluble) and the other one is hydrophobic (organic soluble). • Nonionic surfactants are a class of surfactants, which have no charged groups in their hydrophilic heads. • They are more stable and biocompatible, cheaper and less toxic compared to their anionic, amphoteric, or cationic counterparts.
- 12. 3. Charged Molecule • Charged molecules increase the stability of the vesicles by the addition of charged groups the bilayer of vesicles. • They increase surface charge density and thereby prevent vesicles aggregation.
- 13. Factors Affecting Physico-Chemical Properties of Niosomes Various factors that affect the physico-chemical properties of niosomes : 1. Choice of surfactants: • A surfactant used for preparation of niosomes must have a hydrophilic head and a hydrophobic tail. • The hydrophobic tail may consist of one or two alkyl or perfluoroalkyl groups or, in some cases, a single steroidal group. • The ether-type surfactants with single-chain alkyl tail is more toxic than corresponding dialkyl ether chain. • The ester-type surfactants are chemically less stable than ether-type surfactants and the former is less toxic than the latter due to ester-linked surfactant degraded by esterases to triglycerides and fatty acid in vivo. • The surfactants with alkyl chain length from C12 to C18 are suitable for preparation of noisome. 2. Nature of encapsulated drug: • The physico-chemical properties of encapsulated drug influence charge and rigidity of the niosome bilayer. • The drug interacts with surfactant head groups and develops the charge that creates mutual repulsion between surfactant bilayers, and hence increases vesicle size. • The aggregation of vesicles is prevented due to the charge development on bilayer. • The effect of the nature of drug on formation vesicle is given in Table 1.
- 14. Table 1: Effect of the nature of drug on formation of niosomes 3. Hydrophilic-Lipophilic balance (HLB) of the surfactant : • HLB is a dimensionless parameter, which is the indication of the solubility of the surfactant molecule. • The HLB value describes the balance between the hydrophilic portion to the lipophilic portion of the non- ionic surfactant. • The lower HLB refers to more lipophilic surfactant and the higher HLB to more hydrophilic surfactant. • HLB value of surfactant is more important for niosomes preparation as shown in Table 2.
- 15. 4. Critical packing parameter of the surfactant: The geometry of vesicles formed is depend on the critical packing parameter of the surfactant. It is calculated from the following equation, CPP=V/Ica Where, CPP = Critical packing parameter V = Hydrophobic group volume Ic = Critical hydrophobic group length a = Area of hydrophilic head group Figure 2: Critical packing parameter
- 16. 5. Cholesterol contents: • The concentration of cholesterol depends on HLB values of surfactant. • The surfactant/lipid ratio is in the range of 10-30 mM (1-2.5% w/w), it may influence the physical properties and structure of niosomes. • Appropriate quantity of cholesterol increase the hydrodynamic diameter and entrapment efficiency. • High concentration of cholesterol decrease the release rate of the drugs due to increase in the rigidity of bilayer. 6. Method of preparation • Different methods are used to prepare the niosomes suspension . • Reverse phase evaporation method gives small size vesicles. • Hand shaking method give larger vesicles than ether injection method. • Niosomes prepared by transmembrane pH gradient method gives niosomes with greater entrapment efficiency and better retention of entrapped drug.
- 17. • Injection method • Thin Film hydration method • Sonication • Reverse phase evaporation • The “Bubble” method • Micro fluidization. • Multiple membrane extrusion • Transmembrane pH gradient drug uptake • Formation of Niosomes from Proniosomes Methods of preparation
- 18. 1. Injection method A) Ether injection method • Slow injection of an ether solution of niosomal ingredients into an aqueous medium at high temperature. • A mixture of surfactant and cholesterol is dissolved in ether (20 ml) and injected into an aqueous phase (4 ml) using a 14- gauge needle syringe 60°C . • Niosomes in the form of large unilamellar vesicles (LUV) are formed. B) Ethanol injection method • Ethanol injection method offers advantage that it avoids both sonication and high pressure. • In this technique, surfactant dissolved in ethanol and forcefully injected in aqueous media using syringe. • The whole system stirred using magnetic stirrer in order to evaporate ethanol which results in formation of niosomal vesicles. Figure 3: ILLUSTRATION OF ETHER AND ETHANOL INJECTION METHOD
- 19. 2. Thin Film hydration method Figure 4: PREPARATION OF NIOSOME BY HAND SHAKING METHOD
- 20. 3. sonication Two techniques of sonication are employed a. Bath sonication and b. Probe sonication (Figure 5). In probe sonication technique: Drug solution in PBS is added into cholesterol/non-ionic surfactant mixtures. The whole system is allowed to sonicate for 3 minutes at 60°C through probe sonicator which results in nano sized vesicles. Probe sonication is one of the techniques to reduce the particle size of niosomes. Bath sonication is done after film hydration technique for achieving prolonged release & longer duration of action. (b)(a) FIGURE 5 : PREPARATION OF NIOSOME BYA) BATH SONICATOR B) PROBE SONICATOR
- 21. 4. Reverse phase evaporation:
- 22. 5. The Bubble method: • It is novel technique for the one step preparation of liposomes and niosomes without the use of organic solvents. • The bubbling unit consists of round-bottomed flask with three necks positioned in water bath to control the temperature. • Water-cooled reflux and thermometer are positioned in the first and second neck and nitrogen supply through the third neck • Cholesterol and surfactant are dispersed together in the buffer (pH 7.4) at 70°C, the dispersion mixed for 15 secs with high shear homogenizer and immediately afterwards “bubbled” at 70°C using nitrogen gas. FIGURE 6 : ASSEMBLY OF BUBBLING UNIT
- 23. 6. Micro fluidization This is a recent technique to prepare small MLVS. A microfluidizer is used to pump the fluid at a very high pressure (10,000 psi) through a screen. It is then forced along defined micro channels, which direct two streams of fluid to collide together at right angles, thereby affecting a very efficient transfer of energy. The lipids/surfactants can be introduced into the fluidizer. The fluid collected can be recycled until spherical vesicles are obtained. Uniform and small sized vesicles are obtained. FIGURE 7 : Micro- Fluidization
- 24. 7. Multiple membrane extrusion method • In this method, mixture of cholesterol, non-ionic surfactant and dicetyl phosphate is solubilized in an organic phase and further evaporated to produce transparent film. • The film is dried in desiccator followed by hydration using aqueous phase containing drug. • The whole system is then extruded via series of polycarbonate membranes (Figure 8). • The resulting suspension contains vesicles of uniform size. FIGURE 8 : REPRESENTATION OF MULTIPLE MEMBRANE EXTRUSION METHOD
- 25. 8.Transmembrane pH gradient drug uptake: • In this method cholesterol and non-ionic surfactants are dissolved in organic solvent like chloroform. • The resultant mixture is then vaporized using rotary evaporator to produce watery film on inner surface of the RBF. • Hydration of film is done using aqueous 300 mM citric acid solution (pH 4.0) with the help of cyclo- mixer which gives suspension with multilamellar vesicles. • Resultant suspension is frozen and thawed 3 times. Further it is sonicated to produce niosomal suspension which is stirred at high speed on addition of aqueous drug solution. • pH of the system is increased to 7.0-7.2 with 1M disodium phosphate followed by heating at 60°C for 10 minutes leads to formation of drug loaded niosomal dispersion. FIGURE 9 : REMOTE LOADING TECHNIQUE
- 26. 9. Formation of Niosomes from Proniosomes: • Proniosome technique includes the coating of a water-soluble carrier such as sorbitol and mannitol with surfactant. • The coating process results in the formation of a dry formulation. This preparation is termed “Proniosomes” which requires to be hydrated before being used. • The niosomes are formed by the addition of the aqueous phase. This method helps in reducing physical stability problems such as the aggregation, leaking, and fusion problem and provides convenience in dosing, distribution, transportation, and storage showing improved results compared to conventional niosomes. FIGURE 10 : Preparation of niosomes from proniosomes
- 27. TABLE 3 : TECHNIQUES USED TO EVALUATE NIOSOMES Characterization
- 28. 7. In-vitro methods for niosomes Franz diffusion cell The in vitro diffusion studies can be performed by using Franz diffusion cell. Proniosomes is placed in the donor chamber of a Franz diffusion cell fitted with a cellophane membrane. The proniosomes is then dialyzed against a suitable dissolution medium at room temperature; the samples are withdrawn from the medium at suitable intervals, and analyzed for drug content using suitable method (U.V spectroscopy, HPLC, etc.) .The maintenance of sink condition is essential. 8. In vivo release study • In vivo release study was performed using albino rats. • These albino rats were differentiated into various groups. • By means of appropriate disposal syringe, a niosomal suspension was injected intravenously through a tail vein for in vivo study. 9. Stability studies • To determine the stability of niosomes, the optimized batch was stored in airtight sealed vials at different temperatures. • Surface characteristics and percentage drug retained in niosomes and niosomes derived from proniosomes were selected as parameters for evaluation of the stability, since instability of the formulation would reflect in drug leakage and a decrease in the percentage drug retained. • The niosomes were sampled at regular intervals of time (0,1,2 and 3 months ),observed for color change, surface characteristics and tested for the percentage drug retained after being hydrated to form niosomes and analyzed by suitable analytical methods(UV spectroscopy, HPLC methods etc).
- 29. 1) Anti-neoplastic treatment 2) Leishmaniasis treatment 3) Studying immune response 4) Transdermal drug delivery system 5) Niosomes as drug carriers 6) Ophthalmic drug delivery 7) Drug targeting Applications
- 30. 1. Anti-neoplastic Treatment • Doxorubicin, the anthracyclic antibiotic with broad spectrum anti-tumor activity, is formulated in niosomal preparation for targeted delivery. • Niosomal delivery of this drug to mice bearing S-180 tumor increased their life span and decreased the rate of proliferation of sarcoma. • Niosomal entrapment increased the half-life of the drug, prolonged its circulation and altered its metabolism. • Intravenous administration of methotrexate entrapped in niosomes to S-180 tumor bearing mice resulted in total regression of tumor and also higher plasma level and slower elimination. 2. Leishmaniasis Treatment • Leishmaniasis is a disease caused by parasite genus Leishmania which invades the cells of the liver and spleen. • Most Commonly prescribed drugs for the treatment are the derivatives of antimony – which, in higher concentrations – can cause liver, cardiac and kidney damage. • Use of niosomes as a drug carrier showed that it is possible to administer the drug at high levels without the triggering the side effects, and thus showed greater efficacy in treatment.
- 31. 3. Studying immune response • Due to their immunological selectivity, low toxicity and greater stability; niosomes are being used to study the nature of the immune response provoked by antigens. • Non-ionic surfactant vesicles have clearly demonstrated their ability to function as adjuvants following parenteral administration with a number of different antigens and peptides. 4. Transdermal Drug Delivery System • Niosomes have application in topical and transdermal products both containing hydrophobic and hydrophilic drugs. • Drugs encapsulated for topical and transdermal delivery are lidocaine, estradiol, cyclosporin, erythromycin, alpha-interferon etc. • Slow penetration of drug through skin is the major drawback of transdermal route of delivery. An increase in the penetration rate has been achieved by transdermal delivery of drug incorporated in niosomes.
- 32. 5. Niosomes as Drug Carriers • Niosomes have also been used as carriers for iobitridol, a diagnostic agent used for X-ray imaging. • Topical niosomes may serve as solubilization matrix, as a local depot for sustained release of dermally active compounds, as penetration enhancers, or as rate-limiting membrane barrier for the modulation of systemic absorption of drugs. 6. Ophthalmic drug delivery • From ocular dosage form like ophthalmic solution, suspension and ointment it is difficult to achieve • excellent bioavailability of drug due to the tear production, impermeability of corneal epithelium,non productive absorption and transient residence time. • Niosomal and liposomal delivery systems can be used to achieve good bioavailability of drug. • Bioadhesive-coated niosomal formulation of acetazolamide prepared from span 60, cholesterol stearylamine or dicetyl phosphate exhibits more tendencies for reduction of intraocular pressure as compared to marketed formulation (Dorzolamide). 7. Drug Targeting • Niosomes possess beneficial ability of targeting site of action. • Targeting of drugs to reticulo-endothelial system (RES) is successfully done using niosomes. • The RES holds up niosome vesicles and this uptake of niosomes is influenced by opsonins (circulating serum factors). Opsonins render the niosome for clearance. • This process of localization of active pharmaceutical ingredient can be useful in the treatment of cancer cells, different parasitic infections and can also be applicable to target particular organ other than RES40.
- 33. MARKETED PRODUCTS • Lancome has come out with a variety of anti-ageing products which are based on niosomes Formulations. Niosomes Preparation in the Market is – Lancôme TABLE 4: LIST OF NIOSOME FORMULATION
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