LIPOSOMES: NOVEL DRUG DELIVERY CARRIER
Patel Chirag J*, Asija Rajesh, Asija Sangeeta, Mangukia Dhruv
Maharishi Arvind Institute of Pharmacy,
Department of pharmaceutics, Jaipur,
Amongst the various carriers, few drug carriers reached the stages of clinical trials where liposome shows strong potential for effective drug delivery to the site of action. Liposomes are vesicles having concentric phospholipid bilayers. Molecules from low molecular weight to high molecular weight have been incorporated in liposomes. The water soluble compounds/drugs are present in aqueous compartments while lipid soluble compounds/drugs and amphiphilic compounds/drugs insert themselves in phospholipid bilayers. Drug encapsulated in liposomes include doxorubin, cisplatin, vincristin, melphalan, sarcolycin, daunorubicin, etoposide, etc. The liposomes containing drugs can be administrated by many routes (intravenous, oral inhalation, local application, ocular) and these can be used for the treatment of various diseases. Their predominance in drug delivery and targeting has enabled them to be used as therapeutics tool in fields like tumour targeting, gene and antisense therapy etc. This review discusses the advantages, disadvantages, mechanism, classification, method of preparation, characterization and application of liposomes.
Reference Id: PHARMATUTOR-ART-1352
Liposomes are simple microscopic vesicles in which an aqueous volume is entirely enclosed by a membrane composed of lipid molecule. The name liposome is derived from two Greek words: 'Lipos' meaning fat and 'Soma' meaning body. A liposome can be formed at a variety of sizes as unilamellar or multi-lamellar construction, and its name relates to its structural building blocks, phospholipids, and not to its size1, 2.
The liposomes have emerged as most practically useful carriers for in-vivo drug delivery as majority of reports has concentrated on the use of phospholipid vesicles or liposomes as potential drug carrier systems. Liposomes or lipid based vesicles are microscopic (unilamellar or multilamellar) vesicles that are formed as a result of self-assembly of phospholipids in an aqueous media resulting in closed bilayered structures3. The assembly into closed bilayered structures is a spontaneous process and usually needs some input of energy in the form of physical agitation, sonication, heat etc. Since lipid bilayered membrane encloses an aqueous core, both water and lipid soluble drugs can be successfully entrapped into the liposomes. The lipid soluble or lipophilic drugs get entrapped within the bilayered membrane whereas water soluble or hydrophilic drugs get entrapped in the central aqueous core of the vesicles4.
The use of liposomes for transformation or transfection of DNA into a host cell is known as lipofection. Liposomes can be created by sonicating phospholipids in water. Low shear rates create multilamellar liposomes, which have many layers like an onion. Continued high shear sonication tends to form smaller unilamellar liposomes3, 4.
ADVANTAGES2, 5, 6
1. Liposomes are biocompatible, completely biodegradable, non-toxic, flexible and nonimmunogenic for systemic and non-systemic administrations.
2. Can carry both water and lipid soluble drugs
3. Provide controlled and sustained release
4. Stabilization of entrapped drug from hostile environment
5. Controlled hydration
6. Help to reduce exposure of sensitive tissues to toxic drugs.
7. Drugs can be stabilized from oxidation
8. Targeted drug delivery or site specific drug delivery
9. Alter pharmacokinetics and pharmacodynamics of drugs
10. Can incorporate micro and macro molecules
11. Can be administered through various routes
12. Act as reservoir of drugs
13. Can modulate the distribution of drug
14. Therapeutic index of drugs is increased
15. Can modulate the distribution of drug
1. Less stability
2. Low solubility
3. Problem to targeting to various tissue due to their large size
4. Short half life
5. Sometimes phospholipid undergoes oxidation and hydrolysis like reaction.
6. Leakage and fusion of encapsulated drug / molecules
7. High production cost
8. Quick uptake by cells of R.E.S
9. Allergic reactions may occur to liposomal constituents
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