Liposomes application

The "stealth" concept may offer two other opportunities for liposome application (1) Conventional immunoliposomes (see Sec. VI.C) have been shown to be removed rapidly firom the circulation by the MPS (Peeters et al., 1987). The combination of the stealth approach for longer circulation with the attachment of antibodies or antibody fragments may provide a means of delivery of drugs to their sites of action with a high degree of specificity. This could be useful for treating leukemia, graft-vs.-host diseases, and HIV disease. 

Barenholz Y. Liposome application problems and prospects. Curr Opin Colloid Interface Sci 2001 6 66-77. 

Coupling of Peptides to the Surface of Liposomes—Application to Liposome-Based Synthetic Vaccines... 

J-L Rigaud, B Pitard, D Levy. Reconstitution of membrane proteins into liposomes application to energy-transducing membrane proteins. Biochim Biophys Acta 1231 223-246, 1995. 

Barenholz, Y. (2001), Liposome application Problems and prospects, Curr. Opin. Coll. Interf. Sci., 6, 66-77. 

Efforts to promote medical applications of liposomes have permitted the development of several new drug formulations applicable to a broad range of therapeutics. One of the main areas of liposomes application is cancer therapy, A great number of scientists worldwide have focused their work on drug discovery or the improvement of the efficacy and reduction of the toxicity of known drugs. Two of the main problems in cancer chemotherapy are the toxicity of the known anticancer drugs and the multi drug resistance of certain cancer cells. 

Schuber F, Said Hassane F, Frisch B (2007) Coupling of peptides to the surface of liposomes - Application to liposome-based synthetic vaccines. In Gregoriadis G (ed) Liposome technology, 3rd edn. Informa Healthcare, New York, USA, pp 111-130... 

D. D. Lasic, Liposomes From Physics to Applications, Elsevier, Amsterdam, 1993. 

The development of monoalkyl phosphate as a low skin irritating anionic surfactant is accented in a review with 30 references on monoalkyl phosphate salts, including surface-active properties, cutaneous effects, and applications to paste and liquid-type skin cleansers, and also phosphorylation reactions from the viewpoint of industrial production [26]. Amine salts of acrylate ester polymers, which are physiologically acceptable and useful as surfactants, are prepared by transesterification of alkyl acrylate polymers with 4-morpholinethanol or the alkanolamines and fatty alcohols or alkoxylated alkylphenols, and neutralizing with carboxylic or phosphoric acid. The polymer salt was used as an emulsifying agent for oils and waxes [70]. Preparation of pharmaceutical liposomes with surfactants derived from phosphoric acid is described in [279]. Lipid bilayer vesicles comprise an anionic or zwitterionic surfactant which when dispersed in H20 at a temperature above the phase transition temperature is in a micellar phase and a second lipid which is a single-chain fatty acid, fatty acid ester, or fatty alcohol which is in an emulsion phase, and cholesterol or a derivative. 

The application of modified electrodes for the assay of antibodies in senun preparations using redox indicators encapsuled into antigene marked liposomes attached to an electrode surface was suggested First model studies towards this goal make use of ferricyanide ions entrapped in synthetic vesicles. 

VI. SELECTED EXAMPLES OF POTENTIAL MEDICAL APPLICATIONS OF LIPOSOMES... 

Because of their ability to carry a wide variety of pharmaceuticals, liposomes have been studied for many different therapeutic situations, Therefore, the literature on this topic is abundant. Excellent reviews are available (e.g., Poznansky and Juliano, 1984 Gregoriadis, 1984, 1988b). We will restrict ourselves to the description of certain applications which illustrate the potential benefits of the use of liposomes in the field of drug delivery. 

One approach where the characteristics of the liposomal carrier system are well matched to the intended therapeutic application is the delivery of drugs to the MPS. Because of their particulate nature, the major route of clearance of liposomes, when administered in vivo by a variety of routes, is phagocytosis by MPS cells, especially macrophages in liver and spleen. Obviously, this "natural" fate of liposomes in vivo is an advantage if one attempts to treat diseases... 

A variety of other clinically important infections, such as brucellosis, listeriosis, salmonellosis, and various Mycobacterium infections, are of interest as these are often localized in organs rich in MPS cells. Liposome encapsulation has been demonstrated to improve therapeutic indices of several drugs in a number of infectious models. The natural avidity of macrophages for liposomes can also be exploited in the application of the vesicles as carriers of immunomodulators to activate these cells to an microbicidal, antiviral, or tumoricidal state. These studies were recently reviewed by Emmen and Storm (1987), Popescu et al. (1987), and Alving (1988). In addition to the treatment of "old" infectious diseases, the concept of MPS-directed drug delivery is of considerable interest for the therapy AIDS, possibly enabling control of human immunodeficiency virus replication in human macrophages. 

Liposomes have been studied to improve the ocular availability of drugs after application to the eye or after intravitreal injection. Besides, a liposomal eye drop formulation for the treatment of dry eye symptoms was developed and entered the clinical phase II stage (Guo et al., 1988). 

Browning, J. L. (1981). NMR studies of the structural and motional properties of phospholipids in membranes, in Liposomes From Physical Structure to Therapeutic Applications (C. G. Knight, ed.), Elsevier, Amsterdam, pp. 189-242. 

Eppstein, D. A., and Feigner, P. L. (1988). Applications of liposome formulations for antimicrobial/antiviral therapy, in Liposomes as Drug Carriers Recent Trends and Progress (G. Gregoriadis, ed.), John Wiley and Sons, Chichester, pp. 311-323. 

Knight, C. G. (ed.) (1981). Liposomes From Physical Structure to Therapeutic Applications. Elsevier, Amsterdam. 

---