Cellulose is a natural polymer compound. Its chemical s […]
Cellulose is a natural polymer compound. Its chemical structure is a polysaccharide macromolecule with anhydrous β-glucose as the base ring. There is one primary hydroxyl group and two secondary hydroxyl groups on each base ring. Through chemical modification, a series of cellulose derivatives can be obtained, and cellulose ether is one of them. Cellulose ether is obtained by reacting cellulose with NaOH, then performing etherification reaction with various functional monomers such as methyl chloride, ethylene oxide, propylene oxide, etc., and washing the by-product salt and cellulose sodium with water. Cellulose ether is an important derivative of cellulose, which can be widely used in medicine and health, daily chemical industry, papermaking, food, medicine, construction, materials and other industries.
Methylcellulose, ethylcellulose, hypromellose, hydroxypropylcellulose, and microcrystalline cellulose are more commonly used in the medical field.
Methylcellulose In the pharmaceutical industry, low- or medium-viscosity methylcellulose can be used as a binder for tablets and can also be used for tablet coating. High-viscosity methylcellulose can be used to disintegrate or as a backbone material for sustained release formulations. Methyl cellulose with high degree of substitution and low viscosity can be used in aqueous coatings, as well as suspending agents, thickeners, emulsion stabilizers, and protective colloids. Highly substituted, high-viscosity methylcellulose can be used in eye drops or as a base material for creams or gels.
2.Ethyl cellulose EC
Ethylcellulose is insoluble in water, but soluble in organic solvents such as ethanol. It also has good film-forming properties and can be used as a film coating for tablets that are sensitive to water. Ethylcellulose film becomes stronger and more durable as its viscosity increases. Used in combination with a water-soluble polymer to regulate the drug diffusion rate of the film-coated layer and used as a slow-release coating layer. The ultra-fine product can be used as the backbone material of the sustained-release preparation for direct compression. In addition, ethyl cellulose can be used as a binder in the wet granulation of ethanol, and is specially used for the granulation and compression of water-sensitive drugs. Can also be used as a thickener in creams, lotions, gels.
3. Hypromellose HPMC
Hypromellose is a multifunctional medicinal adjuvant, which can be used as thickener, dispersant, emulsifier and film-forming agent. As a film coating, adhesive, etc. in oral solid preparations, it can significantly improve the stability and dissolution of the drug, and can enhance the water resistance of tablets. It is one of the raw materials for making plant capsules. It can also be used as a suspending agent in suspensions, as a matrix material in ophthalmic preparations, as a matrix material in hydrophilic gel matrix sustained-release tablets and gastric floating tablets.
4, low-substituted hydroxypropyl cellulose L-HPC
Low-substituted hydroxypropyl cellulose is mainly used as a tablet disintegrant and a binder. Tablets using low-substituted hydroxypropylcellulose as a binder and disintegrant are characterized by easy compression molding and strong applicability, especially tablets that are not easy to form, have high plasticity and brittleness, and add low-substituted hydroxypropylcellulose. It can improve the hardness and brightness of the tablet, can also disintegrate the tablet quickly, and improve the internal quality and curative effect of the tablet.
There are hydrogen bonds between the microcrystalline cellulose molecules, and they are associated with each other under pressure, so they are highly compressible and are often used as binders. When compressed tablets encounter body fluids, water quickly enters the micro- Inside the tablet of crystalline cellulose, hydrogen bonds are immediately broken, so it can be used as a disintegrant. In addition, microcrystalline cellulose has a low density, a large specific volume, and a wide particle size distribution, and is often used as a diluent.