Nanoparticles for Targeted Delivery of Active Agents against Tumor Cells

Abstract

Cancer therapy may still be considered as one of the most challenging issues in pharmaceutical sciences. Various new technologies and molecules have been developed to meet the needs of this devastating disease, but there is a long way to go. One of the most important challenges is finding a drug molecule or drug delivery system which only influences the cancer cells. This has not been achieved so far even though a great deal of research has focused on this goal. Most of the cytotoxic agents used for cancer treatment are toxic in nature and not only have an effect on tumor cells, but also normal cells are damaged when exposed with them. As a result, patients may experience intensive side effects which may lead to an early termination in chemotherapy due to their severity. Targeting the cancer cells specifically and selectively seems to be the best solution for this obstacle. Targeting the cancer cells occurs via two different strategies: passive target-ing and active targeting. The conventional approach used for cancer therapy may be considered a sort of passive targeting. Cytotoxic agents used for cancer treatment select the cancer cells due to their faster growth rate. Inevitably, normal fast growing cells and normal fast dividing cells may damage following conventional chemotherapy. In 1986, Matsumura and Maeda brought up a new concept in passive targeting called enhanced permeation and retention (EPR) effect which was widely used in many researches as an approach for targeting tumor cells. In this strategy, the drug delivery system benefits from defective vasculature, fenestrations, and poor lymphatic drainage in tumor tissues. Utilizing molec-ular targeting moieties is another strategy which is widely used in new researches for targeting tumor cells actively and diminishing chemotherapy side effects. This special issue will primarily address new approaches for passive and active targeted cancer therapy with a focus on nanoparticle formulations specially those ones that specifically and selectively target tumors. There is a peper which describes using a natural protein, atelocollagen for oligonucleotide delivery, and evaluating its biological function. The researchers found that when oligonucleotides were used concomitantly with atelocolla-gen, paracellular flux was enhanced, but when each of these two constituents of the formulation was used separately, no effect was observed. Another paper reviews poly(lactic-co-glycolic acid)-(PLGA-) based nanopar…