Views: 2 Author: Site Editor Publish Time: 2022-12-14 Origin: Site
Microcrystalline cellulose (MCC) is a linear polysaccharide bound by ¦Â-1,4 glucosidic bonds.Free-flowing white or off-white powdery solid product.It is mainly composed of cellulose-based organic matter (about 99.95%) and microcrystalline inorganic matter (about 0.05%, such as ash).The main components of ash are Ca, Si, Mg, Al, Fe and other trace metal elements.MCC is non-fibrous and extremely fluid.Insoluble in water, dilute acids, organic solvents and oils, partially soluble and swelling in dilute alkali solutions, and has high reactivity in the processes of carboxymethylation, acetylation and esterification.The source of microcrystalline cellulose is obtained by post-hydrolysis of plant cellulose.The general process is: hydrolysis of ¦Á-cellulose with dilute inorganic acid solution, wherein ¦Á-cellulose can be obtained from fiber pulp of cellulose-containing plants After hydrolysis the cellulose is filtered, purified, and the water slurry is spray-dried to form porous particles with a wide particle size distribution.Microcrystalline cellulose (Microcrystalline cellulose, MCC) is a free-flowing extremely fine short rod-shaped or powder-like porous particle that is hydrolyzed by dilute acid to the limiting degree of polymerization (LOOP) of natural cellulose.The color is white or nearly white. Odorless and tasteless, the particle size is generally 20-80 Lm, and the limiting degree of polymerization (LODP) is 15-375; it is not fibrous and has strong fluidity.It is insoluble in water, dilute acid, organic solvent and oil, partially dissolves and moistens in dilute alkali solution, and has high reactivity in the process of carboxymethylation, acetylation and esterification.Due to its special properties such as low degree of polymerization and large specific surface area, microcrystalline cellulose is widely used in medicine, food, cosmetics and light chemical industry.
In the pharmaceutical industry, microcrystalline cellulose is often used as an adsorbent, suspending agent, diluent, and disintegrating agent.Microcrystalline cellulose is widely used in pharmaceutical preparations, mainly as diluents and binders in oral tablets and capsules, not only for wet granulation but also for dry direct compression.It also has certain lubricating and disintegrating effects, which is very useful in tablet preparation.Because there are hydrogen bonds between microcrystalline cellulose molecules, hydrogen bonds are associated under pressure, so it has high compressibility, and is often used as a binder; when the compressed tablet encounters liquid, water quickly enters the containing Inside the tablet, the hydrogen bonds of microcrystalline cellulose are broken immediately, so it can be used as a disintegrant.Therefore, it is an excipient widely used in tablet production, which can improve the hardness of the tablet. For example, in the preparation of rifampicin tablets, MCC and starch (6.25:1 mass ratio) can be mixed with various raw materials and then directly pressed into tablets.The product disintegrates into a mist within lm min. And the content remains unchanged within the validity period, And can improve drug stability well. As another example, due to the addition of microcrystalline cellulose, the dissolution rate of prednisone acetate and berberine acetate (berberine hydrochloride) tablets increased to more than 80%.The traditional granulation process is not required when microcrystalline cellulose is used as an auxiliary material for tablet compression.For example, MCC is added in the preparation of Kebiqing tablets, which solves the serious sticky phenomenon that occurs when Kebiqing wet granulated tablets are easy to absorb moisture. And disintegrates quickly.Microcrystalline cellulose can also be used as a sustained release agent for pharmaceuticals.The slow-release process is that the active substance enters the porous structure of the carrier.The active substance is contained by intermolecular hydrogen bonds, and the active substance is fixed after drying. When the active substance is released, water diffuses in the capillary system of the polymer carrier to cause swelling, and the chemical bond between the carrier base and the immobilized active substance is destroyed, and the active substance is released slowly.
1.The biggest application feature of microcrystalline cellulose in solid preparations is its high compressibility.Compared with other solid pharmaceutical excipients, this is due to the existence of hydrogen bonds between microcrystalline cellulose molecules, and hydrogen bonds under pressure Association, and thus a high degree of compressibility, can increase the hardness of the tablet.Therefore, it is often used as a dry binder; at the same time, when the compressed tablet encounters liquid, the water quickly enters the tablet containing microcrystalline cellulose, and the hydrogen bond is immediately broken, so it can also be used as a disintegrant. Therefore, it is widely used in tablet production.
2.Microcrystalline cellulose has high water absorption.On the one hand, this feature has good slurry absorption ability in the wet granulation process, and the binder/wetting agent has enough space to use, or add other functions to the binder Non-toxic excipients, the operation is more controllable; on the other hand, the wettability is good, and in the wet granulation process, the wetting uniformity of the material can be increased, which is beneficial to the uniformity of granulation and the content uniformity of the final product; the third On the one hand, the high water absorption of microcrystals leads to strong hygroscopicity of the preparation.Simple microcrystals can absorb moisture for 5 days under the condition of RH75%, and the weight gain of moisture absorption exceeds 5%, and RH92.5% for 5 days, the weight gain exceeds 10%. When the crystallite ratio is high, pay attention to the problem of moisture absorption stability.Under normal storage conditions, the moisture content of the crystallite is generally about 3%~5%, and it is relatively stable;
3.The secondary compression formability of microcrystalline cellulose is poor, and lactose is relatively better at this time;
4.Because microcrystalline cellulose is insoluble in water, there will be a "bottom pressing" phenomenon during the dissolution process, that is, microcrystals accumulate at the bottom of the dissolution vessel in the later stage of dissolution, resulting in incomplete release of API.Therefore, for insoluble drugs, the general microcrystal ratio is recommended No more than 30%, if bottom pressure occurs, reduce the proportion of microcrystals, or increase the dissolution speed (50 75rpm)
5.In the different type systems of microcrystalline cellulose, the general balance relationship is: the better the fluidity, the lower the formability.