As drug carriers

Phospholipids e.g. form spontaneously multilamellar concentric bilayer vesicles73 > if they are suspended e.g. by a mixer in an excess of aqueous solution. In the multilamellar vesicles lipid bilayers are separated by layers of the aqueous medium 74-78) which are involved in stabilizing the liposomes. By sonification they are dispersed to unilamellar liposomes with an outer diameter of 250-300 A and an internal one of 150-200 A. Therefore the aqueous phase within the liposome is separated by a bimolecular lipid layer with a thickness of 50 A. Liposomes are used as models for biological membranes and as drug carriers. 

Polymeric microparticles have been studied and developed for several years. Their contribution in the pharmacy field is of utmost importance in order to improve the efficiency of oral delivery of drugs. As drug carriers, polymer-based microparticles may avoid the early degradation of active molecules in undesirable sites of the gastrointestinal tract, mask unpleasant taste of drugs, reduce doses and side effects and improve bioavailability. Also, they allow the production of site-specific drug targeting, which consists of a suitable approach for the delivery of active molecules into desired tissues or cells in order to increase their efficiency. 

Deong, K. W., Brott, B. C., and Danger, R., Bioerodible polyanhydrides as drug-carrier matrices. I. Characterization, degradation and release characteristics, J. Biomed. Mater. Res., 19, 941-955, 1985. 

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. 

Gregoriadis, G. (ed.) (1988b). Liposomes as Drug Carriers Recent Trends and Progress. John Wiley and Sons, Chichester. 

Weinstein, J. N., and Leserman, L. D. (1984). Liposomes as drug carriers in cancer chemotherapy, Pharmacol. Ther., 24. 207-233. 

Size and homogeneity of liposomes are important in their use as drug carriers, since these characters affect the pharmacokinetics and distribution of liposomes in vivo. Light scattering, electron microscopy, NMR, and gel filtration are used for evaluating liposomal size and homogeneity (32,33)... 

Liposomes as Drug Carriers Gregoriadis, G., Ed., John Wiley Sons Ltd. New York, NY, 1987. 

Polymers, being macromolecules of considerable size and weight, have many limitations when used either as drugs or as drug carriers (1). One of the most serious limitations is the existence of epithelial or endothelial barriers (2). However, macromolecules can be transported by a vesicular process known as transcytosis (3,4). In transcytosis, a polymer can be shuttled across an epithelial cell by first... 

R Bodmeier, P Maincent. Polymeric dispersions as drug carriers. In HA Lieberman, MM Rieger, GS Banker, eds. Pharmaceutical Dosage Forms Disperse Systems, Vol. 3. 2nd ed. New York Marcel Dekker, 1998, pp 87-128. 

SH Klang, M Parnas, S Benita. Emulsions as drug carriers - possibilities, limitations and future perspectives. In RH Muller, S. Benita, BHL Bohm, eds. Emulsions and Nanosuspensions for the Formulation of Poorly Soluble Drugs. Stuttgart Medpharm Scientific Publishers, 1998, pp 31-78. 

Nanoparticles are solid colloidal particles ranging in size from 10 to 1000 nm. They can be used as drug carriers, with the drug encapsulated, dissolved, adsorbed, or covalently attached [79,80]. The small size of... 

Soluble macromolecules of both natural and synthetic origin have been used as drug carriers. When compared with the particulate carriers, soluble macromolecules (a) encounter fewer barriers to their movement around the body and can enter into many organs by transport across capillary endothelium or in... 

E. Tomlinson and J. J. Burger, Monolithic albumin particles as drug carriers, in Polymers in Controlled Drug Delivery (L. Ilium and S. S. Davis, eds.), Wright, Bristol, 1987, p. 25. 

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