1. Liposomes: Formation, preparation, properties and applications
Dr. S.S.Apte
Professor, Univ. College of Pharm. Sci., Kakatiya University, Warangal
Presently:
NDDS Divn, Natco Research Centre
Hyderabad

2. Liposomal Anthracycline Antibiotics Used in Therapy
Product
Drug
Marketed By
Registration
Year
DaunoXome
Daunorubicin citrate
NeXstar Pharmaceutical Inc.
England
Sweden USA
1995 r r r.
Doxil
Doxorubicin
Sequus Pharmaceutical Inc.
USA
1995
Caelix
Schering-Plough
Selected European Countries
1995 r.

3. Definition of Liposomes
Liposomes are spherical, self closed structures composed of curved lipid bilayers which entrap part of the solvent, in which they freely float, into their interior. They may consist of one or several concentric membranes; their size ranges from 20 nm to several dozens µm, while thickness of the membrane is around 4 nm.

4. Salient features Discovered in 1968 by Alec Bangham
Delivery system for hydrophilic, lipophilic, and amphiphilic APIs
Solubilization of lipophilic and amphiphilic APIs
Protection of the API
Reduction of side effects - toxicity of the active
Sustained release
Drug targeting
Low application dose

5. Classification of Liposomes
SUV = Small Unilamellar Vesicles
LUV = Large Unilamellar Vesicles
MLV = Multilamellar Vesicles
LLC = Lamellar Liquid Crystalline Phase
MVV = Multivesicular vesicles
Liposomes are composed of one to several
hundreds concentric membranes

6. liposomes (phospholipids + Cholesterol)
Vesicular delivery systems
liposomes (phospholipids + Cholesterol)
Vesicles
Niosomes (Nonionic surfactants +cholesterol)

7. Preparation of vesicles:
Film casting via organic solvent
film hydration
ether-ethanol injection
Reverse phase evaporation
Through mixed micellar solution
Mechanical methods

8. Characterization of vesicles:
Size and size distribution - Dynamic light scattering
Electron microscopy
Coulter counter
Number of lamellae - NMR spectroscopy
small angle X ray scatter
Charge - Microelectrophoresis
Entrapment efficiency - Gel filtration
Capture volume ultrafiltration
dialysis
protamine aggregation
ultracentrifugation
Release - Dialysis

9. Liposomal Delivery of Anti-Cancer Agents
Slow Release: reduced peak levels of free drug and prolonged tumor exposure
Change in Biodistribution: avoiding drug deposition in certain tissues will reduce tissue-specific toxicities
Tumor Targeting: passive accumulation by enhanced permeability and retention (EPR) effect

10. Phospholipids in topical pharmaceutical applications
Drug
Effects
Benzoyl peroxide
Flurbiprofen
Diclofenac
Heparin
Clindamycin phosphate
Aciclovir
Menthol & camphor
N,N-diethyl-meta-toluamide (DEET)
Povidone-Iodine
Tamoxifen
Econazol, Miconazol
Glycolic acid
Bethametasone 17-benzoate
improved drug delivery; higher anti-bacterial efficacy
better penetration; improved efficacy in pain treatment
improved drug delivery; higher drug efficacy
improved penetration; higher drug efficacy
sustained release, drug efficacy improvement
enhanced penetration
enhanced penetration, rapid onset of action
controlled release, inhibition of absorption
improved drug delivery & efficacy
improved penetration and drug retention in the skin
drug retention in the skin
controlled release
penetration enhancement