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Liposomes by Mr. Vishal Shelke

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Liposomes by Mr. Vishal Shelke
https://youtube.com/vishalshelke99
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Liposomes

Sub :- Novel Drug Delievery Systems, Sterile Products Formulation & Technology
M.Pharm Sem II
Savitribai Phule Pune University

Introduction :-
Liposomes are vesicular structures composed of a lipid bilayer. These vesicular structures can be used as a vehicle for administration of nutrients and drugs.
Liposomes are concentric bilayered vesicles in which an aqueous volume is entirely enclosed by a membranous lipid bilayer.
Liposomes consist of Cholesterol, Phospholipid and drug molecule

Classification of Liposomes :-

Small Unilamellar (SUV) [20-100nm]

Medium Unilamellar (MUV)

Large Unilamellar (LUV) [>100nm]

Giant Unilamellar (GUV) [>1μm]

Multi Lamellar Vesicles (MLV) [0.5nm]

Oligolamellar Vesicles (OLV)

Multi Vesicular (MV) [>1μm]

ADVANTAGES

Provides selective passive targeting to tumor tissues.
Increased efficacy and therapeutic index.
Increased stability via encapsulation.
Reduction in toxicity of the encapsulated agents.
Improved pharmacokinetic effects (reduced elimination, increased circulation life times).

DISADVANTAGES
low solubility
short half life
high production  cost
less stability
leakage and fusion of encapsulated drug
sometimes the phospholipid layer undergoes oxidation and hydrolysis reaction

Methods of Preparation of Liposomes
1 Mechanical Dispersion Method
Lipid film hydration by
hand shaken MLVs
Micro emulsification
Sonication
French pressure cell
Dried reconstituted vesicles
Membrane Extrusion Method

2 Solvent Dispersion Method
Ethanol injection
Ether injection
Double emulsion vesicles
Reverse phase
evaporation vesicles

3 Detergent Removal Method

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Liposomes by Mr. Vishal Shelke

  1. 1.  Introduction  Classification of Liposomes  Advantages & Disadvantages  Methods of Preparation  Vesicular ocular drug delivery system – liposomes  Evaluation of Liposomes  Applications  References
  2. 2. Introduction :- Liposomes are vesicular structures composed of a lipid bilayer. These vesicular structures can be used as a vehicle for administration of nutrients and drugs.  Liposomes are concentric bilayered vesicles in which an aqueous volume is entirely enclosed by a membranous lipid bilayer.  Liposomes consist of Cholesterol, Phospholipid and drug molecule
  3. 3. Classification of Liposomes :- •Small Unilamellar (SUV) [20-100nm] •Medium Unilamellar (MUV) •Large Unilamellar (LUV) [>100nm] •Giant Unilamellar (GUV) [>1μm] •Multi Lamellar Vesicles (MLV) [0.5nm] •Oligolamellar Vesicles (OLV) •Multi Vesicular (MV) [>1μm]
  4. 4. ADVANTAGES •Provides selective passive targeting to tumor tissues. •Increased efficacy and therapeutic index. •Increased stability via encapsulation. •Reduction in toxicity of the encapsulated agents. •Improved pharmacokinetic effects (reduced elimination, increased circulation life times).
  5. 5. DISADVANTAGES •low solubility •short half life •high production cost •less stability •leakage and fusion of encapsulated drug •sometimes the phospholipid layer undergoes oxidation and hydrolysis reaction
  6. 6. Methods of Preparation of Liposomes Mechanical Dispersion Method Solvent Dispersion Method Lipid film hydration by hand shaken MLVs Micro emulsification Sonication French pressure cell Dried reconstituted vesicles Membrane Extrusion Method Ethanol injection Ether injection Double emulsion vesicles Reverse phase evaporation vesicles Detergent Removal Method
  7. 7. Lipid film hydration by Hand Shaken MLVs Lipid Mixture in Chloroform: Methanol (2:1v/v) in 250 ml flask Rotate the flask on rotary evaporator for 60 rpm at 300 C for 15 mins. Lyophilizer to remove residual solvents Hydration of lipid in saline phosphate buffer for 30 mins Allow to stand for 2 hrs. at RT for swelling to give MLVs.
  8. 8. Microemulsification Microfluidizer
  9. 9. Sonication
  10. 10. French Pressure Cell Method This method involves the extrusion of MLV at 20,000 psi at 4°C through a small orifice. The method has several advantages over sonication method. The method is simple, rapid, reproducible and involves gentle handling of unstable materials. The resulting liposomes are somewhat larger than sonicated SUVs. Dried Reconstituted Vesicles (DRVs) In this method, water soluble materials to be entrapped, are added to the suspension of empty SUV’s & they are dried together, so the material for inclusion is present in the dried precursor lipid before the final step of addition of aqueous medium.
  11. 11.   Membrane Extrusion Method  Liposomes passed through membrane of defined pore size.  LUVs as well as MLVs can be processed.  Vesicle contents are exchanged with dispersion medium during breaking and resealing of phospholipid bilayers as they pass through the polycarbonate membrane.  For high entrapment, the water soluble compounds should be present in suspending medium during the extrusion process.
  12. 12. Solvent Dispersion Methods Ethanol Injection Method
  13. 13. Ether Injection Method
  14. 14. Double Emulsification Method In this process, an active ingredient is first dissolved in an aqueous phase which is then emulsified in an organic solvent of a polymer to make a primary w/o emulsion.  This primary emulsion is further mixed in an emulsifier- containing aqueous solution (w2) to make a w/o/w double emulsion.  The removal of the solvent leaves microspheres in the aqueous continuous phase, making it possible to collect them by filtering or centrifuging.
  15. 15. Reverse Phase Evaporation Method  Lipid, organic solvent and aqueous solution are i. mixed, ii. sonicated, iii. formation of w/o emulsion.  Then evaporated to remove the organic solvent.  Lipids form a phospholipid bilayer on vigorous shaking , water droplets collapse and formation of LUV’s takes place.
  16. 16. Detergent Removal Method The detergents (cholate, triton X-100, octylglucoside) at their critical micelles concentrations have been used to solubilize lipids. As the detergent is removed the micelles become progressively richer in phospholipid and finally combine to form LUVs. The detergents are removed by dialysis . A commercial device called LIPOPREP which is a dialysis system is available for the removal of detergents. Other techniques have been used for the removal of detergents are Gel Chromatography involving a column of Sephadex G-25.
  17. 17. VESICULAR OCULAR DRUG DELIEVERY SYSTEM – LIPOSOMES Deliver the drug at a predetermined rate and should release the drug at the specific site of action in therapeutically active concentration. Drug delivery via vesicles provides prolonged as well as controlled drug delivery at the targeted corneal surface. They are having an intimate contact with the corneal and conjunctival surfaces. Which is desirable for drugs that are poorly absorbed, the drugs with low partition coefficient, poor solubility or those with medium to high molecular weights.
  18. 18. 1. Visual Appearance 2. % Drug Encapsulated 3. Phase Behaviour 4. Drug Release Rate 5. Determination of Lamillarity 6. Particle Size
  19. 19.   Cancer chemotherapy – Liposomes are successfully used to entrap anticancer drugs. This increases circulation life time, protects from metabolic degradation.  Liposomes as carrier of drug in oral treatment – • Steroids used for arthritis can be incorporated into large MLVs. • Alteration in blood glucose levels in diabetic animals was obtained by oral administration of liposome encapsulated insulin.  Liposomes for pulmonary delivery – Inhalational devices like nebulizers are use to produce an aerosol of droplets containing liposomes.
  20. 20.  Liposomes can enhance the permeation of poorly absorbed drug molecules by binding to the corneal surface and improving residence time E.g. Ciprofloxacin  Liposomes can improve pharmacokinetic profile, enhance therapeutic effect, and reduce toxicity associated with higher dose E.g. fluconazole  Liposomes have been widely investigated for the treatment of both anterior and posterior segment eye disorders.
  21. 21. 1. Controlled And Novel Drug Delivery’, “Jain N.K.’’, CBS Publisher And Distributors. Page No. 304-352. 2. Targeted And Controlled Drug Delivery, Novel Carrier Systems “Vyas S.P. And Khar R.K.’’, CBS Publishers Page No.181 -195 3. Liposome- As Drug Carriers-international Journal Of Pharmacy & Life Sciences - Himanshu Anwekar, Sitasharan Patel And A.K Singhai. 4. https://slideshare.net 5. https://pharmatutor.org
  22. 22. Also available on Youtube! Youtube :- https://youtube.com/vishalshelke99 Instagram :- https://instagram.com/vishal_stagram
  23. 23. 24

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