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What are the common excipients in PVPK30?
Jan 24, 2018

A wetting agent is a liquid that can moisten the material to produce a strong enough viscosity to make particles. The wetting agent itself has no stickiness, but it can moisten the material and induce the stickiness of the material itself, so that it can be formed into soft material and made into particles. Adhesives refer to the aggregation of particles that are cohesionless or less viscous, or the compressed solid powder or viscous liquid.


The common wetting agents and adhesives are used in the production of tablets as follows:

1. water

Generally, purified water is used, and the water itself is sticky. When the material (such as Chinese medicine extract or other viscous components) contains water and produce viscous components, wetting with water can induce stickiness and make suitable particles. But when the water is used as a wetting agent, because of the high drying temperature, it is not suitable for the drugs that are heat-resistant, easily metamorphosed by water or easy to dissolve in water. In addition, because the water is easily absorbed by the material, it is difficult to disperse and moisten evenly, resulting in agglomeration, dissolution and other phenomena. The particles are also unevenly distributed, which affects the quality of tablets. It is rarely used alone, often with the low concentration of starch or different concentrations of ethanol instead of.


2. ethanol

Where the drug itself is sticky, but water can cause deterioration or after wetting viscous strong granulation that made of particles or difficult; dry and hard, not easy to produce tablet disintegration or one-sided pits and other phenomena, can choose the suitable concentration of ethanol as a wetting agent, such as vitamin C tablets, Dried Yeast Tablets etc.. The concentration of ethanol depends on the nature and temperature of the drug, usually 30%~70% or thicker. The concentration of ethanol should be slightly higher when the water solubility, viscosity and temperature of the drug are high, whereas the concentration of the drug can be slightly lower. The higher the concentration of ethanol, the less the viscosity produced by the wetting, the loosening of the prepared particles and the rapid disintegration of the pressed tablets. When the alcohol is used as a wetting agent, it should be quickly stirred and immediately granulated to reduce the volatilization.


3. hydroxypropyl methylene cellulose

Hydroxypropyl methylene cellulose (HPMC) is a white powder, odourless and tasteless. It has considerable stability for heat, light and humidity, and can be dissolved in water and some polar organic solvents. In water, it can expand to form a viscous solution, and heating and cooling can be converted to each other in the two states of the solution and the gel. In addition HPMC has been used as a dispersing agent, thickening agent and coating material, widely used as tablet binder, pressing tablet appearance, hardness, fast disintegration, dissolution, and no change during storage; is easy to use, suitable for a variety of different tablets available; the dry powder, solution or with starch combination. As a binder, the usual concentration is 2%~5%, the viscosity is 5~50Pa x s, and the dosage is generally 1%~4% of the prescription amount.


4. (PVPK30) polyvidone

Povidone (PVP) is white or milky white powder, has a special odor, has a stable chemical property, can be dissolved in water and ethanol and become a viscous colloidal liquid. It is a good adhesive. The general dosage is 0.5%~2% of the total weight of the tablet. PVP has many specifications because of its different molecular weight or viscosity. The common K30 type tablet is prepared, its average molecular weight is 60000, and 10% (w/w) aqueous solution has certain viscosity. For hygrothermal sensitive drugs, PVP organic solution (usually ethanol solution) is used to granulate, which can avoid the influence of moisture and dry at lower temperature. For hydrophobic drugs, PVP aqueous solution is used as an adhesive, which is not only easy to uniformly moisten, but also makes the hydrophobic particles surface hydrophilic, which is conducive to the disintegration and dissolution of drugs. As an adhesive, its aqueous solution, alcohol solution or solid powder can be applied. PVP dry powder can also be used as a dry binder for direct pressing. The ethanol solution of 3%~15% is often used to granulate water sensitive drugs, and the particles made can be highly compressible. 5%PVP anhydrous ethanol solution can be used to granulate the mixed powder of acid and alkali in effervescent tablets, and the chemical reaction can be avoided in the presence of water. This product is also a good adhesive for chewing tablets.


5. starch pulp

It is commonly known as starch paste, one of the commonly used adhesives or wetting agents. It is made of mixing starch in cold water, heating to gelatinization, or suspending with a small amount of cold water, and adding boiling water to make paste. The pasting temperature of about 70~75 DEG C, pay attention to temperature to prepare starch and heating time have effect on the viscosity.


6. syrup

The aqueous solution of syrup is sucrose aqueous solution. Its viscosity varies with different concentration. Its concentration is 50%~70% (g/g), and its adhesive force is strong. It is suitable for botanical drugs with fiber and loose texture and strong elasticity. Chemical drugs that are loose and easy to lose crystalline water are also available. Strong acid or strong basic drugs can cause the conversion of sucrose to produce humidifying, which is not beneficial to the tablet, so the drugs should not be used.


7. other cellulose derivatives

In addition to the above HPMC, the commonly used cellulose derivatives, such as methyl cellulose (MC) and sodium carboxymethyl cellulose (CMC-Na), can all be used as the adhesives for the tablets. It can be used for its solution, and it can also be wetted with dry powder after wetting. MC and CMC-Na can be dissolved in water and become strong sticky solutions. The commonly used concentration is 2%~10%.


8. mortar

The common 10%~20% gelatin solution and the Arabia glue solution of 10%~25% are used. The stickiness of the glue is strong and should be used for insulation to prevent gelation. Paste made of tablet hardness large, easy to loose and can not be used for drug starch granulation. It is also suitable for the buccal tablet, which does not need to disintegrate in the water or needs to extend the action time.








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