Liposomes as drug delivery vehicles

Wright S, et al. Antibody-directed liposomes as drug-delivery vehicles, Adv Drug Deliv Rev 1989, 3, 343-389. 

Hawthorne, M. R Shelly, K., Liposomes as drug delivery vehicles for boron agents. J. Neuro-Oncol. 1997,33, 53-58. 

Shinkai and coworkers prepared numerous novel amphiphilic crowns (Shinkai, 1990) and incorporated them into membranes, formed membranes from them, or used them in liquid crystalline assemblies to control properties (He et al., 1990). Interest in this area continues. Four chiral amphiphilic crown ethers were recently reported that recognize enantiomeric amino acids when examined as Langmuir films (Badis et al., 2004). Finally, it is interesting to note that liposomes formed from amphiphiles (e.g., crown ethers) having neutral headgroups (i. e., niosomes) have been studied as drug delivery vehicles (Uchegbu and Vyas, 1998). 

Surfactants having two alkyl chains can pack in a similar manner to the phospholipids (see Box 6.4 for examples). Vesicle formation by the dialkyldimethylammonium cationic surfactants has been studied extensively. As with liposomes, sonication of the turbid solution formed when the surfactant is dispersed in water leads ultimately to the formation of optically transparent solutions which may contain single-compartment vesicles. For example, sonication of dioctadecyldimethyl-ammonium chloride for 30 s gives a turbid solution containing bilayer vesicles of 250-450 nm diameter, while sonication for 15 min produces a clear solution containing monolayer vesicles of diameter 100-150 nm. The main use of such systems has been as membrane models rather than as drug delivery vehicles because of the toxicity of ionic surfactants. 

Liposomes and nanoliposomes prepared by the heating method (HM-liposomes) have been employed successfully as gene transfer vectors (38,46,50) as well as drug delivery vehicles (51). Incorporation of plasmid DNA molecules, which are sensitive to high temperatures, to the HM-liposomes was carried out at room temperature by incubation of DNA with the empty, pre-formed, HM-liposomes (38, 46, 50). Another important feature of this method is that it can be easily adapted from small to industrial scales. 

Pierre MBR, Costa IdSM. Liposomal systems as drug delivery vehicles for dermal and transdermal applications. Archives of Dermatological Research. 2011 303(9) 607-621. 

Chandra, S., Agrawal, A. K., and Gupta, C. M. (1991) Chloroquine delivery to erythrocytes in Plasmodium berghei-infected mice using antibody-bearing liposomes as drug vehicles. J. Biosci. 16, 137-144. 

Thus, the hydrophilic head group and hydrophobic tail of lipids ensure assembly into the oriented bilayer array of cell membranes. The amphiphilic sheet, bilayer, and vesicle are now familiar mofits in biomimetic materials and structures. Synthetic liposomes are employed as biocompatible, biodegradable drug-delivery vehicles. Amphiphile assemblies may serve as templates mono-disperse nanoparticles are synthesized inside reverse micelles, and inorganic structures and materials such as ceramic tubules or mesoporous silica are formed around tubular micelles, rather as inorganics are patterned by vesicles in the formation of the exoskeletons of radiolarians and diatoms. 

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