Drug Excipients Restricting Drug Delivery System

With the progress of science, the research of pharmaceutical preparations has entered the era of drug delivery system. Drug release systems will play an important role in the fields of chemical pharmaceuticals, biotechnology and biotherapy in the future. The lag of drug excipients development has become an important factor restricting the development of drug delivery system in China. Some experts suggested that we should pay attention to the role of pharmaceutical excipients in pharmaceutical research, increase support, and promote the rapid and healthy development of domestic excipient industry.

Because the drug release function of the drug delivery system is completely supported by excipients, the research and application of new excipients, the re-evaluation of existing excipient functions and the research of new preparation technology should be the first choice for pharmaceutical enterprises in China. Shen Huifeng, a senior expert in pharmaceutical preparations in China, believes that active drugs in pharmaceutical formulations are the main part of substance and determine the whole direction of action; excipients ensure that drugs are selectively transported to tissues in a certain procedure, prevent inactivation of drugs before release from the main body, and make drugs in the body at a certain speed. And time, in a certain part of the release. Therefore, the formulation composed of suitable excipients plays an active and key role in the practical application and efficacy of drugs.

In recent years, the role of pharmaceutical excipients in drug delivery system has been increasing, and they are widely used. For example, polymer materials such as ethyl cellulose, light propylmethyl cellulose, polyacrylic acid vinegar series are mainly used in the design and manufacture of oral sustained/controlled release drug delivery systems. Deethylphthalide chitosan and glycoprotein are also used, and the application of inclusion complex controlled release is increasing. For example, gelatin, starch, albumin, polylactic acid, poly (lactic acid), poly (light acetic acid-lactic acid) copolymer, poly (methylphthalamide), polypropylene-based cool, ethyl cellulose and other macromolecule materials are commonly used in microcapsules and microparticle controlled-release preparations; biodegradable polymers (poly (lactic acid, poly (glycolic acid) and poly (glycolic acid-lactic acid) The transmission of proteins and skin drugs can reduce the dosage of drug delivery, increase the stability of protein and achieve localization and constant release rate; both dextran and chitosan can be decomposed under the action of bacterial enzymes in the colon, but not easily hydrolyzed in the stomach and small intestine; they are suitable materials for colon-targeting drug delivery system; they can be used in colon-targeting adhesive drug delivery system. Most of the carriers are non-specific carriers, such as alginate, cellulose derivatives, dextran, gelatin, pectin, chitosan and so on. Carbomer is the most widely used carrier. Copolymers of methacrylic acid, light propyl methyl cellulose acetate and cellulose acetate phthalate can be used as enteric-coated materials. Cyclodextrin is decomposed into oligosaccharides by colonic microbial fermentation, but it is not easy to hydrolyze, so it will not release drugs in the stomach and small intestine, and can be used to prepare colon-targeted drug delivery system.

"For a long time, the pharmaceutical industry in China has focused on the development of raw materials rather than the research of preparations. There is still a big gap between China's drug release technology and the world's advanced level. Taking sustained and controlled release preparations as an example, there are more than 200 kinds abroad, but less than 100 kinds are produced normally in China. Tu Jiasheng, a professor at the School of Pharmacy, China Pharmaceutical University, pointed out that the research of drug release system in China is mainly traceable, and the development and application of new drug release technology is not very much. There are many reasons for the lag of development, but the reasons for excipients can not be ignored. In terms of the development of Chinese medicine delivery system, besides the complex components of Chinese medicine preparations, the material basis of their pharmacodynamics is difficult to determine; the process of Chinese medicine preparations is relatively backward, the content of science and technology is not high, the competitiveness is weak, and the added value is low; there are still some difficulties in the study of compound preparations, and other factors, new excipients have not yet been developed and applied to Chinese medicine preparations. Midway is also an important factor. At present, although more than a dozen new excipients have been used in traditional Chinese medicine preparations, only cyclodextrin and sodium fusimethylcellulose are used more.

According to Tu Jiasheng, the quality of excipients in China is not stable and can not meet the requirements of drug release technology. So some of the new slow-release and controlled-release dosage forms are still in the laboratory, unable to carry out large-scale production, and difficult to enter the market. In addition, China lags far behind developed countries in research and development of new excipients and quality control of pharmaceutical excipients. He suggested that the relevant state departments should actively organize, closely cooperate with enterprises, plan scientifically, unify management, and strengthen the research on improving the quality of pharmaceutical excipients. We should focus on the development of related excipients for various preparations, such as new adhesives, disintegrants, coating materials, pigments, cosolvents, surfactants and so on. Enteric-coated excipients of cellulose derivatives, soybean phospholipids for injection, incubation phospholipids and poloxamer for injection should be strengthened. In addition, through policy incentives and other means, accelerate the rapid and healthy development of China's accessories industry.