Liposomal NanoPharmaceuticals
Submitted by lucky_pharmacist on Fri, 05/23/2008 - 10:40.
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Liposomes were discovered in 1961 by Alec D. Bangham who was studying phospholipids and blood clotting, and since then they became very versatile tools in biology, biochemistry and medicine.
Liposomes are nano size artificial vesicles of spherical shape that can be produced from natural phospholipids and cholesterol. Bangham discovered that phospholipids combined with water immediately forms a bi-layered sphere because one end of each molecule is water soluble, while the opposite end is water insoluble (see Figure bellow).
Liposomes are broadly classified by their structure
· Multilamellar liposomes: Spherically concentric multilamellar (many bilayers) structures
· Unilamellar liposomes: Spherical concentric unilamellar (one bilayer) structures
The properties of liposomes in addition to the general properties of surfactants those make them useful for different applications are
· Structural stability on dilution
· Varying permeability of the bilayer to different molecules.
Ability to entrap both water soluble and insoluble substances and deliver them into desired environments.The size, lamellarity (unilamellar or multilamellar) and lipid composition of the bilayers influence many of the important properties like the fluidity, permeability, stability and structure -these can be controlled and customized to serve specific needs. The properties are also influenced by external parameters like the temperature, ionic strength and the presence of certain
molecules nearby.
Liposomes is extensively studied for encapsulation of drugs. When lipid self assemble to liposomes water-soluble drugs will be trapped inside the liposomal cavity; fat-soluble drugs are incorporated within phospholipid bi-layer. The lipid bilayer of the liposome can fuse with other bilayers (e.g. cell membrane), thus delivering the liposome contents.
dear lcky very good
dear lcky very good presentation about liposomes diagrammatic representation is very good
praveen
I have tried to represent
I have tried to represent in simple way and in a way I was able to understand the concept.
Dear Lucky.
Dear Lucky, Nice presentation abt Liposomes. What is the possibility do you feel for working on liposomes in our laboratories like we work on microparticles, nanoparticles etc. Shall we expect liposomes in nano sizes practically, generally we will have agglomerates with micro- or milli- sizes. What is your comment on that?
{eswar} G.S.N.Koteswara Rao
microparticles, nanoparticles
Liposomes have nano to micron size range. You can refer the article mentioned below to get some idea of the preparation method.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1502115&blobtype=p...
You may also refer many of the articles on liposomes which describe its preparation. As you know for most of the research work the formulations are prepared at lab scale so I think it is possible to prepare the liposomes at lab scale.
Thank you...
Thank you for your nice conversation and discussion.
{eswar} G.S.N.Koteswara Rao
I am always there for all friends
No need for thanks I am always there for my freinds and would also like to improve my knowledge by getting some more info which I may have missed in my presentation.
anti-tubercular drugs...
i think recently attempts are being laid over research for targetting drug delivery of many anti-bacterial drugs against granuloma infections like tuberculosis using micro-particles.....So won't it be possible to target the same using liposomes???
Just go through the below
Just go through the below mentioned paper you will get information about use of liposomes & nanoliposomes of antitumor drugs in animal model.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1502115&blobtype=p...
And yes I definitely feel the area is wide open and liposomes can be used for targeted systems, just proper study and efforts in that direction are required.
microparticle??
Is micropartiple a better substitue of liposome for targetted as well as sustained drug delivery system???
Every dosage form has its own advantage
Dear Shubhranshu, It was nice to see your comment. I personally feel each dosage form has its own advantages and applications and every form brings question about the use of others.
To the extent I have read, the use of microparticles has been limited to vaccine, peptide delivery and now being implied for antibiotics and other drugs. I'll try n explain the details in one of my blog.