What is nanomedicine
Nanomaterials refer to materials with a spatial size of 1-100 nm (see Figure 1). Nanomedicine refers to various types of nanomaterials that can play a role in the treatment, prevention and control, and diagnosis of diseases. Nanomedicine is an emerging product generated by the combination of nanotechnology and medicine. Nanomedicine can be divided into two categories: nano-particle medicine, which means that the medicine itself is nano-sized, the medicine is made into nanometer size by certain means. Such as suspension, tablet, capsule and so on; Nano-carrier medicine refers to loading medicine into nano-carriers, and use the effects of nano-carriers to better exert their curative effect. Such as liposomes, nanospheres, and nanocapsules.
There are several nano-drugs on the market, such as Doxil, Visudyne and Vyxeos. The most advanced RNA drug in the clinic, Patisiran, uses lipid nanoparticle (LNP) technology. The properties of nanomedicine can be used to control when and where the active pharmaceutical ingredients act in the body.
Advantages of nanomedicine
After biological products, nanomedicine represents the next era of drug innovation. Existing research has proven revolutionary new treatment strategies such as improved efficacy, reduced side effects, and personalized medicine. Compared with traditional drugs, nanomedicine has many advantages: it can change the properties of the drug and increase the solubility of poorly soluble drugs; reduce the degradation of the drug in the circulation process; concentrate the drug in the predetermined site of action, enhance the efficacy of the drug while reducing side effects; in addition, The application of nano-carriers in drug delivery systems can weaken or eliminate the limitations of biological barriers on the effects of drugs, and provide new technical methods for disease diagnosis and treatment and disease progress monitoring.
Principles of nanomedicine design
Although various nano-carriers are used in the development of anti-tumor nano-drugs, most of them are based on two basic design principles:
1. crease the accumulation of tumor tissues through the tumor’s high penetration and retention effect (EPR) to improve the efficacy;
2. rough the long circulation effect of nanomedicine (PEG surface modification, etc.), reduce the clearance of nanomedicine by the reticuloendothelial system in the body and increase its concentration in plasma, thereby reducing the uptake of nanomedicine by normal tissues and reducing side effects, while enhancing Nanomedicine is effective in tumor EPR to increase curative effect. Although these two principles have been repeatedly verified in animal tumor models, most anti-tumor nanomedicines did not improve the efficacy in clinical trials and led to failure.
The design of nanomedicine should be drug-specific and nanocarrier-specific. It is necessary to thoroughly evaluate the biodistribution of nanomedicine to understand its unique efficacy and safety, which can improve the success rate of clinical transformation of preclinical models. For the current research hotspot of anti-tumor nano-drug design and development, some scholars have provided new directions for guidance, which can be summarized as follows:
(1) To evaluate the unique physical and chemical properties, pharmacokinetics, and potential problems of each drug, And its corresponding efficacy and toxicity characteristics, targeted design of nano-medicine.
(2) Study the characteristics of the distribution of nanocarriers in the body and how to change the targeting of drugs to different tissues to determine its efficacy and safety.
(3) The delivery of nano-drugs to target organs with tumors is a necessary but not a sufficient condition. Nano-drug design needs to deliver drugs to various target cells in the tumor microenvironment to improve curative effect.
The above principles are also applicable to the design of large-molecule anti-tumor nano-drugs (such as mRNA, siRNA, antisense nucleic acid (ASO), microRNA (miRNA) and nucleic acid aptamer (Aptamer), etc.)
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