Application Prospects of Targeted Nano Drug Delivery System
Targeted drugs were proposed by German scientist and Nobel Prize winner Ehrlich in 1906 and have a history of more than 100 years. Until the late 1970s, with the advancement of molecular biology, cell biology, and materials science, targeted formulations developed rapidly, and products began to be marketed. The nano drug delivery system is distributed in specific organs, tissues, cells, and even intracellular structures in the body through passive targeting, active targeting, physical and chemical targeting, etc., and changes the distribution of prototype drugs in vivo.
With the leapfrog development of life sciences, human understanding of disease pathogenesis and drug action mechanisms has transitioned from a macroscopic overall level to a microscopic cellular level or even a molecular level. Nano drug delivery systems are increasingly researched in tumor targeting, brain targeting, liver targeting, lung targeting, kidney targeting, lymphatic targeting, cellular and intracellular targeting, etc. Safety and industrialization research is also gaining increasing attention.
Advantages of Targeted Nano Drug Delivery System
Targeted formulations can reduce the toxic and side effects of drugs, improve the drug treatment index, and ultimately achieve the ultimate goal of drug delivery: safety and efficiency. The stronger the drug targeting, the lower the incidence of adverse reactions and the smaller the damage to the body. Targeted drug delivery system research has evolved from the initial tissue and organ targeting to the current cell and organelle targeting, and the location of selective drug delivery is becoming more and more precise. The advantages of targeted nano preparations include: ① achieve cell targeting; ② can cross certain physiological barriers; ③ achieve simultaneous delivery of multiple drugs or co-delivery of drugs and contrast agents; ④ can improve the stability of macromolecular drugs in vitro and in vivo. The economic value of nano-targeted formulations is enormous. With the expiry of the patents of the blockbuster drugs of international pharmaceutical companies, it is becoming more and more difficult to develop new chemical entity molecular products. It is a good choice to use nanotechnology to develop new formulation products. The nano-targeted drug delivery system can improve the curative effect of the drug and reduce its toxic and side effects without developing new physical drug molecules. It can replace the previous varieties and complete the product upgrade. In addition, an important difference from the development of new chemical drugs is that after a new formulation variety is developed, it can be applied to similar drugs, and the development of a series of products to form a technological platform advantage can greatly reduce product development and production costs.
Targeted Nano-Drug Delivery System’s Challenges
At present, the literature on the research of targeted nano drug delivery systems is increasing. Researchers have combined with the latest developments in other disciplines to design many innovative solutions. The experimental results are encouraging, but these research results have so far been translated into very few the number of actual products. The reason may be the specificity of the targeted nano drug delivery system. From the initial prescription design to the later safety evaluation and industrial production, all face a series of challenges. The following describes the challenges and countermeasures for targeted nano-preparations from three aspects: safety, quality control, and industrial production.
- The Safety of Nano Drug Delivery System
Medicines are special products related to life safety. When a drug exerts its functions of diagnosis, treatment and physiological adjustment, it is necessary to ensure its safety. When the material size reaches the nanometer level, some unique characteristics such as quantum size effect, size effect, surface effect, and dielectric confinement effect will appear. It has been found that the surface properties of nanoparticles such as shape, particle size, and charge greatly affect the toxicity. In the past, the safety evaluation methods used for chemical or biological products may not be suitable for nano preparations, or at least additional supplementary multi-disciplinary experimental research on the characteristics of nano carriers needs to be supplemented to determine the safety of nano drug carriers.
- Quality Control of Nano Drug Delivery System
There are many factors that affect the quality of nano preparations, such as particle size, shape, charge, surface characteristics, modification position and number, etc. Establishing corresponding detection methods and quality standards to ensure consistent quality between different batches of products is a long-term and arduous project. The stable and controllable quality of medicine mainly depends on the stable and controllable production process, and quality control is only an auxiliary means.
Nano formulations are prone to stability problems because of their high dispersion characteristics. The first is the chemical, biological and physicochemical stability of the formulation. Nanoparticles are prone to adsorption and aggregation, causing nanoparticles behavior changes in vivo. If micron-sized particles are formed, they may even block microvessels and cause thrombosis. The stability of the carrier material also needs to be considered. The degradation of the carrier material will bring about changes in the quality of the preparation, resulting in targeted changes in the body, and the decomposition products may produce serious toxic side effects (such as the hydrolysis of phospholipids into lysophospholipids). If the surface of the nanoparticles is modified with ligands, the latter will fall off or transfer during the storage of the formulation, which will lead to a reduction or even loss of the targeting of the formulation.
- Industrial Production of Nano Drug Delivery System
The scale-up study of preparation production process is an important content and necessary stage of preparation research and development, it is the transition and foundation of laboratory research and industrial production, and it is also the process of further perfecting and optimizing the preparation process. The development equipment and operating conditions of the laboratory are generally different from industrial production, and the prescription process selected by the laboratory is not necessarily suitable for industrial production. Therefore, it is necessary to optimize and determine the key production links and important process parameters in the pilot stage according to the characteristics of the formulation dosage form, drugs and production equipment. Generally speaking, the preparation method is simple, reliable, durable, reproducible, easy to adjust, and is similar to or the same as the type of industrial production equipment, so the production scale-up is relatively smooth; otherwise, the production process may be difficult to control, the product Can not meet the expected quality standards.