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Containing amino polysaccharide chitosan as a new type of polymer material, in nature reserves are abundant, widespread in the shrimp, crabs and insects, shells and algae, fungi into the cell wall, is second only to cellulose the second largest natural polymer material. Because chitosan has certain health effects, as Health Products Use a long time. Domestic and foreign scholars in recent years, a number of research and found that chitosan can also serve as a new Pharmaceutical Excipients Use, especially its unique active ingredients of drug controlled release and targeted positioning function, has become a pharmaceutical workers the focus of attention and study. More and more pharmaceutical companies are beginning to chitosan used in drug development and production of these new formulations. Chitosan by the deacetylation of chitin, was. Chitin can be generated through a variety of chemically modified derivatives are useful medicinal value of accessories, preparation of new dosage forms in a variety of play accessories by the lack of traditional role and functions. The chitosan is present in Medicine And chemical derivatives of the field of application of one of more chitin. Developed by using chitosan formulations and controlled release of drugs with targeted positioning function, balanced the drug release rate, a decrease of drugs on normal tissue cells of side effects. controlled release formulation of new assistant Chitosan has good biocompatibility and biodegradability. Study confirmed that chitosan coating with different viscosity poly-L-lactic acid (PLLA) microspheres, their burst effect of drug and controlled drug release effect is different, with high viscosity [viscosity range of 384 ± 10cp (mPa . s)] chitosan coated PLLA microspheres with lidocaine not included Yi Wei ball than 1 hour lidocaine release rate of 19.2% was reduced to 14.6%; T50 from 25 hours to 90 hours Further research showed that: high viscosity of chitosan in reducing burst release and controlled drug release terms are better. This study shows that control is to control the viscosity of chitosan chitosan coated PLLA microspheres for the release of the most important factor. More chitosan particles distributed systems (CDS) is a relatively new controlled release technology. This system consists of storeroom and the release layer, release layer of water insoluble polymer and chitosan Powder Composition of the whole digestive tract of drug can be released from CDS pellets. In the stomach, through the controlled release layer of partial dissolution of chitosan, and the release of some drugs; in the small intestine, medicine ball in from the CDS to constant release; in the large intestine, CDS ball will accelerate the decomposition of residual chitosan powder , and the CDS will be released in the residual drugs, the release rate can be dispersed water insoluble chitosan layer thickness to control the release. For colon drug delivery system, must be casing layer to avoid the drugs in the stomach to release the ball from the CDS, so there is enteric coating of the CDS (E-CDS) pellets applied to colon drug delivery system. Thus, CDS applicable not only to release but also for colon-specific drug delivery system. Chitosan derivatives on protein drugs can reduce the burst release. N-(2 - hydroxy) - propyl -3 - trimethyl ammonium chitosan chloride (HTCC) is a water-soluble chitosan derivatives, HTCC and 3 by sodium (TPP) ion gel formed HTCC nanoparticles. With bovine serum (BSA), for example, when as a model protein drug, was wrapped in when HTCC nanoparticles (particle size of 110 ~ 180 nm), in vitro studies show effects in the burst followed by a slow continuous release process which can increase the concentration of BSA, also can improve the encapsulation efficiency, if the TPP concentration from 0.5 mg / ml to 0.7 mg / ml, will enable the encapsulation efficiency increased from 46.7% to 90%, and delayed release ; and to gather Glycol (PEG) or sodium alginate, modified HTCC nanoparticles, make BSA significantly reduced the burst release, burst rate dropped from 42% to 18%; when the PEG concentration from 1.0 mg / ml to 20.0 mg / ml, encapsulation efficiency decreased from 47.6% to 2%; when the concentration of sodium alginate from 0.3 mg / ml to 1.0 mg / ml, the encapsulation efficiency will increase from 14.5% to 25.4%. I am an expert from skeletonmechanicalwatch.com, while we provides the quality product, such as automatic skeleton watch , China mechanical automatic watch, skeleton mechanical watch,and more.
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