Natural cellulose ether is a general term for a series of cellulose derivatives produced by the reaction of alkali cellulose and etherifying agent under certain conditions. It is a product in which the hydroxyl groups on cellulose macromolecules are partially or completely replaced by ether groups. Cellulose ethers are widely used in the fields of petroleum, building materials, coatings, food, medicine, and daily chemicals. In various fields, pharmaceutical-grade products are basically in the middle and high-end fields of the industry, with high added value. Due to strict quality requirements, the production of pharmaceutical-grade cellulose ether is also relatively difficult. It can be said that the quality of pharmaceutical-grade products can basically represent the technical strength of cellulose ether enterprises. Cellulose ether is usually added as a blocker, matrix material and thickener to make sustained-release matrix tablets, gastric-soluble coating materials, sustained-release microcapsule coating materials, sustained-release drug film materials, etc.
Sodium carboxymethyl cellulose：
Carboxymethyl cellulose sodium (CMC-Na) is the cellulose ether variety with the largest production and consumption at home and abroad. It is an ionic cellulose ether made from cotton and wood through alkalization and etherification with chloroacetic acid. CMC-Na is a commonly used pharmaceutical excipient. It is often used as a binder for solid preparations, a thickening agent, a thickening agent, and a suspending agent for liquid preparations. It can also be used as a water-soluble matrix and film-forming material. It is often used as sustained-release drug film material and sustained-release matrix tablet in sustained (controlled) release preparations.
In addition to sodium carboxymethylcellulose as a pharmaceutical excipient, croscarmellose sodium can also be used as a pharmaceutical excipient. Croscarmellose sodium (CCMC-Na) is a water-insoluble product of carboxymethylcellulose reacting with a crosslinking agent at a certain temperature (40-80°C) under the action of an inorganic acid catalyst and purified. As the crosslinking agent, propylene glycol, succinic anhydride, maleic anhydride and adipic anhydride can be used. Croscarmellose sodium is used as a disintegrant for tablets, capsules and granules in oral preparations. It relies on capillary and swelling effects to disintegrate. It has good compressibility and strong disintegration force. Studies have shown that the swelling degree of croscarmellose sodium in water is greater than that of common disintegrants such as low-substituted carmellose sodium and hydrated microcrystalline cellulose.
Methylcellulose：
Methyl cellulose (MC) is a non-ionic cellulose single ether made from cotton and wood through alkalization and methyl chloride etherification. Methylcellulose has excellent water solubility and is stable in the range of pH2.0~13.0. It is widely used in pharmaceutical excipients, and is used in sublingual tablets, intramuscular injections, ophthalmic preparations, oral capsules, oral suspensions, oral tablets and topical preparations. In addition, in sustained-release preparations, MC can be used as hydrophilic gel matrix sustained-release preparations, gastric-soluble coating materials, sustained-release microcapsule coating materials, sustained-release drug film materials, etc.
Hydroxypropyl methyl cellulose：
Hydroxypropyl methylcellulose (HPMC) is a non-ionic cellulose mixed ether made from cotton and wood through alkalization, propylene oxide and methyl chloride etherification. It is odorless, tasteless, non-toxic, soluble in cold water and gelled in hot water. Hydroxypropyl methylcellulose is a cellulose mixed ether variety whose production, dosage and quality have been rapidly increasing in China in the past 15 years. It is also one of the most widely used pharmaceutical excipients at home and abroad. years of history. At present, the application of HPMC is mainly reflected in the following five aspects:
One is as a binder and disintegrant. As a binder, HPMC can make the drug easy to wet, and it can expand hundreds of times after absorbing water, so it can significantly improve the dissolution rate or release rate of the tablet. HPMC has strong viscosity, which can enhance the particle viscosity and improve the compressibility of raw materials with crisp or brittle texture. HPMC with low viscosity can be used as binder and disintegrant, and those with high viscosity can only be used as binder.
The second is as a sustained and controlled release material for oral preparations. HPMC is a commonly used hydrogel matrix material in sustained-release preparations. Low-viscosity grade (5-50mPa·s) HPMC can be used as binder, viscosifier and suspending agent, and high-viscosity grade (4000-100000mPa·s) HPMC can be used to prepare mixed material Blocking agent for capsules, hydrogel matrix extended-release tablets. HPMC is soluble in gastrointestinal fluid, has the advantages of good compressibility, good fluidity, strong drug loading capacity, and drug release characteristics not affected by PH. It is an extremely important hydrophilic carrier material in sustained-release preparation systems and is often used as Hydrophilic gel matrix and coating materials for sustained-release preparations, as well as auxiliary materials for gastric floating preparations and sustained-release drug film preparations.
The third is as a coating film-forming agent. HPMC has good film-forming properties. The film formed by it is uniform, transparent and tough, and it is not easy to stick during production. Especially for drugs that are easy to absorb moisture and are unstable, using it as an isolation layer can greatly improve the stability of the drug and prevent The film changes color. HPMC has a variety of viscosity specifications. If selected properly, the quality and appearance of coated tablets are superior to other materials. The usual concentration is 2% to 10%.
The fourth is as a capsule material. In recent years, with the frequent outbreaks of global animal epidemics, compared with gelatin capsules, vegetable capsules have become the new darling of the pharmaceutical and food industries. Pfizer of the United States has successfully extracted HPMC from natural plants and prepared VcapTM vegetable capsules. Compared with traditional gelatin hollow capsules, plant capsules have the advantages of wide adaptability, no risk of cross-linking reactions and high stability. The drug release rate is relatively stable, and individual differences are small. After disintegration in the human body, it is not absorbed and can be excreted The substance is excreted from the body. In terms of storage conditions, after a large number of tests, it is almost not brittle under low humidity conditions, and the properties of the capsule shell are still stable under high humidity conditions, and the indicators of plant capsules are not affected under extreme storage conditions. With people’s understanding of plant capsules and the transformation of public medicine concepts at home and abroad, the market demand for plant capsules will grow rapidly.
The fifth is as a suspending agent. Suspension-type liquid preparation is a commonly used clinical dosage form, which is a heterogeneous dispersion system in which insoluble solid drugs are dispersed in a liquid dispersion medium. The stability of the system determines the quality of the suspension liquid preparation. HPMC colloidal solution can reduce the solid-liquid interfacial tension, reduce the surface free energy of solid particles, and stabilize the heterogeneous dispersion system. It is an excellent suspending agent. HPMC is used as a thickener for eye drops, with a content of 0.45% to 1.0%.
Hydroxypropyl Cellulose：
Hydroxypropyl cellulose (HPC) is a non-ionic cellulose single ether made from cotton and wood through alkalization and propylene oxide etherification. HPC is usually soluble in water below 40°C and a large number of polar solvents, and its performance is related to the content of hydroxypropyl group and the degree of polymerization. HPC can be compatible with various drugs and has good inertia.
Low-substituted hydroxypropyl cellulose (L-HPC) is mainly used as tablet disintegrant and binder. -HPC can improve the hardness and brightness of the tablet, and can also make the tablet disintegrate quickly, improve the internal quality of the tablet, and improve the curative effect.
Highly substituted hydroxypropyl cellulose (H-HPC) can be used as a binder for tablets, granules, and fine granules in the pharmaceutical field. H-HPC has excellent film-forming properties, and the obtained film is tough and elastic, which can be compared with plasticizers. The performance of the film can be further improved by mixing with other moisture-resistant coating agents, and it is often used as a film coating material for tablets. H-HPC can also be used as a matrix material to prepare matrix sustained-release tablets, sustained-release pellets and double-layer sustained-release tablets.
Hydroxyethyl cellulose
Hydroxyethyl cellulose (HEC) is a non-ionic cellulose single ether made from cotton and wood through alkalization and etherification of ethylene oxide. In the field of medicine, HEC is mainly used as a thickener, colloidal protective agent, adhesive, dispersant, stabilizer, suspending agent, film-forming agent and sustained-release material, and can be applied to topical emulsions, ointments, eye drops, Oral liquid, solid tablet, capsule and other dosage forms. Hydroxyethyl cellulose has been recorded in the US Pharmacopoeia/US National Formulary and the European Pharmacopoeia.
Ethyl cellulose：
Ethyl cellulose (EC) is one of the most widely used water-insoluble cellulose derivatives. EC is non-toxic, stable, insoluble in water, acid or alkali solution, and soluble in organic solvents such as ethanol and methanol. Commonly used solvent is toluene/ethanol as 4/1 (weight) mixed solvent. EC has multiple uses in drug sustained-release preparations, widely used as carriers, microcapsules, and coating film-forming materials for sustained-release preparations, such as tablet blockers, adhesives, and film coating materials , used as a matrix material film to prepare various types of matrix sustained-release tablets, used as a mixed material to prepare coated sustained-release preparations, sustained-release pellets, and used as encapsulation auxiliary materials to prepare sustained-release microcapsules; it can also be widely used as a carrier material For the preparation of solid dispersions; widely used in pharmaceutical technology as a film-forming substance and protective coating, as well as binder and filler. As the protective coating of the tablet, it can reduce the sensitivity of the tablet to humidity and prevent the drug from being affected by moisture, discoloration and deterioration; it can also form a slow-release gel layer, microencapsulate the polymer, and enable the sustained release of the drug effect.