What is a Liposome ?
AN INTRODUCTION TO LIPOSOMES.
Hello dear bloggers here I present my first topic of the month i.e. an introduction to liposomes, in which I will outline the basic introduction of liposomes and the classification of liposomes.
liposomes are a very good carrier molecules of the drug. With the emergence of this technology of encapsulation the many great advances have been made in the field of pharmacy.
What is a Liposome ?
Liposomes are vesicles consisting of a lipid bilayer enclosing an aqueous compartment at the center(1).
The lipid bi-layer used in the liposomes are usually made of phospholipids.
Naturally occurring phospholipids used in liposomes are(3):
synthetic phospholipids used in the liposomes are:
* dioleoyl phosphatidylcholine
* disteroyl phosphatidylcholine
* dioleoyl phosphatidylethanolamine
* distearoyl phosphatidylethanolamine
The phospholipids are arranged in such a way that the hydrophilic head is exposed outside and the lipophillic tails are aliened inside. This makes the liposomes water soluble molecules..
Thus a liopsphere as a whole is an water soluble unit.
Apart from phospholipids other lipids that can be used are: sphingolipids, glycolipids, sterols.
The size of a typical liposome may range from 25 to 5000 nm.
CLASSIFICATION OF LIPOSOMES:
Liposomes are classified based on their structure as
1. Multi-laminar vesicles(MLV): made up of series of concentric bi-layer of lipid enclosing a small internal volume.
2. Oligolamelar vesicles(OLV): constitutes 2 to 10 bi layer of lipids surrounding a large internal volume
3. Unilamellar vesicle(ULV): single layer of lipids
4. Based on the size of the single layer they are further divide into the following types with in ULV as
* Small unilaminar vesicle: size of 20 to 40 nm
* Medium unilaminar vesicle: size of 40 to 80 nm
* Large unilaminar vesicle: size of 100 to 1000 nm
* Gaint unilaminar vesicle: size of more than 1000 nm
Liposome can be incorporated with
* Drugs( antibiotics, antifungals)
* Proteins/polpeptides(including antibiotics)
* Virus and bacteria can be incorporated in the liposomes
Hydrophilic drugs are incorporated with in the central cavity which is hydrophilic
Lipophilic drug molecules are incorporated in the lipid bi layer. As shown below.
This blog does not contain any plagiarized material.
1. Biopharmaceutics and pharmacokinetics a treatise by D.M.Bramhankar and sunil B. jaiswal (first edition reprint 2005) pg.no- 360-361.
2. http://noopurmandrek.files.wordpress.com/2010/09/lipo1.jpg (accessed on 15-04-2011)
3. www.nanobiotec.iqm.unicamp.br/download/liposomas-3.ppt accessed on 15-04-2011)
4. http://www.uni-magdeburg.de/imos/mea_sen/img/pictures/Lipo.jpg (accessed on 15-04-2011)
5. http://www.nanolifenutra.com/images/image_liposome_01.jpg (accessed on 15-04-2011)
6. http://www.azonano.com/work/bFgW9FjRw248U2PRC2In_files/image002.gif (accessed on 15-04-2011)
7. http://upload.wikimedia.org/wikipedia/en/2/28/Liposome.jpg (accessed on 15-04-2011)