Drugs drug carrier

The transport mechanisms that operate in distribution and elimination processes of drugs, drug-carrier conjugates and pro-drugs include convective transport (for example, by blood flow), passive diffusion, facilitated diffusion and active transport by carrier proteins, and, in the case of macromolecules, endocytosis. The kinetics of the particular transport processes depend on the mechanism involved. For example, convective transport is governed by fluid flow and passive diffusion is governed by the concentration gradient, whereas facilitated diffusion, active transport and endocytosis obey saturable MichaeUs-Menten kinetics. 

Silica Aerogels as Host Matrix for Drugs (Drug Carriers)... 

I. Gonda, Crit. Lev. Then Drug Carrier Syst. 6, 273—313 (1990). 

L. Fiume, C. Busi, A. MattioH, and G. Spiuosa, CRC Critical Reviews in Therapeutic Drug Carrier Systems 4, 265—284 (1988). 

MAI composed of PAIE for application to emulsifiers, drug carriers, and ion-exchange resins [60,61]. Poly(per-fluoropropyleneglycol)-b-poly(acrylic acid) was synthesized initiated with an MPI having fluoroalkyl group in the main chain [62]. It was soluble to water, ethanol, and THF, and showed water repellency, oil repellency, antifouling, and resistance to chemicals. 

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. 

Duncan, R. and Kopecek, J. Soluble Synthetic Polymers as Potential Drug Carriers. Vol. 57, pp. 51 —10 . 

Ohya et al. reported poly(ethyleneglycol)-grafted chitosan nanoparticles as peptide drug carriers. The incorporation and release of insulin was dependent on the extent of the reaction of poly(ethyleneglycol) with chitosan [190]. 

Spray-drying of chitosan salt solutions provides chitosan microspheres having diameters close to 2-5 p.m and improved binding fimctionaUty. The chitosan microsphere free-flowing powder is compressible and hence most suitable as a drug carrier [ 195-204]. The following are some examples. 

Anwer K, Rhee BG, Mendiratta SK (2003) Critical Rev Ther Drug Carrier Sys 20 249... 

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. 

The aim of this chapter is to summarize some of the research findings on xylan, a natural polymer extracted from corn cobs, which presents a promising application in the development of colon-specific drug carriers. Physicochemical characterization of the polymer regarding particle size and morphology, composition, rheology, thermal behavior, and crystallinity will be provided. Additionally, research data on its extraction and the development of microparticles based on xylan and prepared by different methods will also be presented and discussed. 

Couvreur, P., Barratt, G., Fattal, E., Legrand, P. Vauthier, C. (2002). Nanocapsule technology A review. Critical Reviews in Therapeutic Drug Carrier Systems, Vol. 19, 2, (March 2002), pp. (99-134), ISSN 0743-4863... 

Kanke, M., Geissler, R. G., Powell, D., Kaplan, A., and De-Luca, P. P., Interaction of microspheres with blood constituents. III. Macrophage phagocytosis of various types of polymeric drug carriers, J. Parent. Sci. Technol., 42, 157, 1988. 

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. 

Heller, J., Biodegradable polymers in controlled drug delivery, CRC Crit. Rev. Ther. Drug Carrier Syst.. 1, 39-90, 1984. 

Arnold, L. J., Dagan, A., and Kaplan, N. O., Poly(L-lysine) as an antineoplastic agent and a tumor-specific drug carrier,... 

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