AN INTRODUCTION TO LIPOSOMES.

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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).

(2)

The lipid bi-layer used in the liposomes are usually made of phospholipids.

Naturally occurring phospholipids used in liposomes are(3):

* phosphatidylcholine,

* phosphatidylethanolamine,

* phosphatidylserine

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..

Lipophillic part

Hydrophilic part

(4)

Thus a liopsphere as a whole is an water soluble unit.

(5)

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

(6)

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.

(7)

This blog does not contain any plagiarized material.

Reference:

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)

About the Author

Nandini's picture
Author: Nandini

Comments

Sravani kompella's picture

hai nandini, A very nice presentation.. What will happen to the liposomes after their action is over?
Nandini's picture

hello sravani thank you for going through my blog and the answer for your question is as the liposomes mimic as the physioolgical molecules they are metabolised physiologically by our body metabolising systems mostly liver.

with regards Nandini. TEAM ASSIMILATORS.

Nandini's picture

hello sravani, thank you for going through my blog. the liposomes are metabolised in the body , as they resemble the natural phaysiological molecules they are metabolised by the general methods of metabolisims. once again the ways of metabolism will vary with the type of the liposome.

with regards Nandini. TEAM ASSIMILATORS.

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