Drug carriers, use

M.M.A. Abdel-Mottaleb, A. Lamprecht, Standardized in vitro drug release test for colloidal drug carriers using modified USP dissolution apparatus I, Drug Dev. Indus. Pharm. 37 (2) (2011) 178-184. 

Ma, H., Zhou, J., Carunm, D., Yu, M.H., Chen, J.F., O Connor, C.J. et al. (2008) Fabrication of magnetic porous hollow silica drug carriers using CaC03/Fej04 composite nanoparticles and cationic... 

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. 

Prior to the study by Chen et al. (140), only one publication discussed the use of the protein casein as a drug carrier (141). Chen et al. systematically compared the many features of albumin and casein microspheres—morphology, drug (adriamycin) incorporation, and release—in an effort to identify important factors in the antitumor effect of this delivery system. 

Rahman, Y. E. (1988). Use of liposomes in metal poisonings and metal storage diseases, in Liposomes as Drug Carriers Recent Trends and Progress (G. Gregoriadis, ed.), John Wiley and Sons, Chichester, pp. 485-495. 

Numerous experimental therapeutics have shown potency in vitro however, when they are tested in vivo, they often lack significant efficacy. This is often attributed to unfavorable pharmacokinetic properties and systemic toxicity, which limit the maximum tolerated dose. These limitations can be overcome by use of drug carriers. Two general types of carrier systems have been designed drug conjugation to macromolecular carriers, such as polymers and proteins and drug encapsulation in nanocarriers, such as liposomes, polymersomes and micelles. 

Probably the most promising polymeric drug carrier system involves polysaccharide molecules. These are natural polymers and are often biodegradable to products that are useful to the host or easily eliminated by the host. Dextrans have been the most extensively used polysaccharide for macromolecular prodrug preparations (79). These materials are biocompatible and the in vivo fate is directly related to their molecular weight. Moreover these macromolecules can be easily targetted to the hepatocytes with D-mannose or L-fucose (20). 

One of the most successful conjugate polymer systems was developed by Duncan and Kopecek (25). The polymer carrier used in their system is poly [N(2-hydroxypropyl) methacrylamide] a biocompatible polymer that was originally developed as a plasma extender. They have evaluated a number of polymer conjugated drugs for cancer chemotherapy with interesting results. The attachment of the drug is through a peptidyl spacer pendent to the polymer backbone. These peptides links are stable in aqueous media but are readily hydrolyzed intracellularly... 

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)... 

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... 

An excellent carrier is needed to deliver a sufficient amount of prostaglandins to the diseased site. Liposomes have been studied for a long time as possible drug carriers. However, the clinical use of liposomes has delayed because of some difficulties in mass production, sterilization, stability and safety. Since 1980 we have attempted to use lipid microspheres (lipid emulsions) instead of liposomes as a better carrier for lipophilic drugs (7). 

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