Tumor-targeted drug delivery systems application

This article focuses on tumor-targeted drug delivery systems. It is divided into two major sections an overview of targeting mechanisms, and some application examples that have demonstrated tumor targeting in preclinical and clinical studies. 

APPLICATIONS OF TUMOR-TARGETED DRUG DELIVERY SYSTEMS... 

The introduction of stimuli sensitivity to the carriers is critical for drug-delivery system (DDS] application to target the controlled release of drugs from the corresponding nanoparticles after accumulation at a specific site (Doi et al., 1986], The stimulus for DDS is temperature, pH or ionic strength. the carriers may degrade or diffuse to release the encapsulated drugs. In particular, the addition of pH sensitivity to nanoparticles is more effective for the DDS application due to the difference of extracellular pH of normal tissue (pH 7.2-7.4] and due to many solid tumors... 

Liposomes form spontaneously when lipids are dispersed in aqueous media. They consist of a bilayer membrane which captures a pool of water in its center. The practical value of liposomes derives from two unioue properties 1) their ability to entrap either water-soluble materials in tne internal water reservoir or liposoluble compounds in the lipid bilayer and 2) their compatibility witn natural membranes, making them safe for medical application. They have attracted considerable interest as delivery systems, such as carriers of drugs to specific targets in the treatment of cancer tumors and in enzyme therapy (1) and in various diagnostic tests using fluorescent makers (2) and radiolabels (3). Liposomes are fragile structures created in water as a result of a delicate balance of interacting forces which arise when amphiphilic compounds are added to water. In most practical applications liposomes have to be... 

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