Problems of Chinese herbal Medical Tablet Production I
Writer： admin Time：2021-03-04 16:04 Browse：℃
Developing medical industry brings about high requirements on drugs quality. People pay more attention to drugs quality instead of only curative effect. However, there are still some technical problems for traditional Chinese medicine production to be solved, although pharmaceutical machinery also upgrades. What we should do is to collect, study and solve the influential problems to improve quality of traditional Chinese medicine.
Traditional Chinese medicine is of complex components and can only be produced by strictly inspected techniques. Immature technique might cause many unstable effects on medicine production.
Advantage and disadvantage of tablet
Tablets refer to the flaky preparations combining API and excipients produced by granulation and pressing. It can be taken orally or externally. As the most widely used preparation in clinical treatment, tablet has a lot of advantages.
1) Accurate dosage. Dosage and API content of tablets conform to formulation for narrow difference. The patients can take tablets in accurate dosage. Besides, the tablets can be embossed with concavity so that each tablet can be split to two or four segments for accurate taking in smaller dosage.
2) Stable quality. Tablets will not be damaged or out of shape during transport and storage. The API content keeps constant for a long time. And tablets are dry and small. Light, air, moisture and dust can have little influence on tablets stability.
3) Convenient taking. There is no need to dissolve tablets, so it’s convenient to carry and take them. And some tablets are coated to cover disagreeable color, taste and smell.
4) Easy identification. Tablets are marked with API name and content and some are dyed, both for easy identification.
5) Low cost. Tablets can be mass produced by automatic machines. And the sanitary conditions can be controlled easily.
But tablets are also insufficient in some aspects, including 1) uneasy taking for kids and the fainting, 2) uneasy disintegration or dissolution in gastrointestinal tract since they go bad in improper storage and 3) loss of volatile components.
In practical production, more and more enterprises find that most tablets of sample production are qualified while the products of pilot-scale or scale-up production are not, although their formulation and technical parameters are the same. The latter products end to stick on the puncher, break and have excessive weight difference and nonuniform content. However, the formulation and technique have been set and even are being declared. It’s hardly possible to change them. If the problems are not solved, the project will fail and the manpower and material resources are wasted at last.
1. Tablet breaking in Chinese herbal tablet pressing
Tablet breaking, or top breaking refers to the phenomenon that the tablet top or bottom splits and then falls. Splitting will lead to rough tablet surface, inaccurate dosage and negative influence on tablet quality. There are mainly three causes for tablet breaking:
1) Equipment
a. Over-pressure of table press machine
In recent years, pharmaceutical equipment has had a rapid development. Traditional Chinese medicine is normally produced by similar machines in the same principle as well as same influential factors. High pressure of tablet press machine might be the first cause for tablet breaking. Granules are pressed quickly. But if the adhesive cannot bear the strong expansion force, tablets will break. In this case, it’s helpful to decrease stress.
b. High speed of tablet press machine
Most workers are paid by piece. Some of them will heighten their income by producing more products in higher speed. Therefore, tablets are not completely pressed and will break later. Besides, high rotating speed might exceed stable rotating speed, causing tablet breaking too. A suggestion is to regulate tablet pressing speed and stick the regulation on the machine to remind the operators.
2) Mould
a. Wider gap between upper punch and middle mould
Some dry powder contains large amount of crude fiber which will rub the mould ceaselessly. The gap between upper punch and middle mould will widen after certain time of use and the produced tablets are very possible to break. To reduce wear and tear to mould, operators can change mould after certain batches.
3) Material
a. Low moisture content of granules
Low moisture will cause difficult granule agglomeration during tablet press. Therefore, during granulation the material feeding speed should be controlled, so is the moisture content during drying. Tablet moisture content normally slides within a certain range. If their moisture content is below the range, the tablets will break. Moisture content should be controlled depending on products’ properties.
b. Much fine powder in granules
Fine powder will influence tablet tightness and cause tablet breaking. In this case, the operators should control excipient feeding speed and time during granulation. Besides, the granule size should also be regulated in reference to size distribution to narrow difference between batches. It’s normal to contain fine powder in a proportion of not higher than 10% but the particular content should be determined depending on the material.
c. Low viscosity of granules
Most traditional Chinese preparations need adhesives during granulation. Some factories use syrup in the concentration of 60%. Except factors of API, syrup dosage will obviously affect granule viscosity. Therefore, type and dosage of adhesives should be carefully determined.
2. Loose tablet in tablet pressing
Loose tablets are mainly of weak hardness, while weak hardness will cause inaccurate tablet dosage due to breaking and wear and tear during packaging and transport. There are mainly two kinds of factors influencing tablet hardness.
1) Equipment
a. Lacking pressure of tablet press machine
This phenomenon occurs rarely and is always caused by lacking pressure supply. Tablets are not stable as they are compressed. The discharged tablets are normally not hardened. In this case, the machine pressure should be increased moderately. Besides, the tablet hardness can be tested for further pressure adjustment and regulation.
b. High rotating speed and short compressing time
Rotating speed and compressing time is closely related to operators’ operation. The factories can regulate proper speed and pressure limit in reference to investigation and stick the regulation on the machine. Setting speed limit is also helpful.
c. No pre-compression
If the pre-compressing rollers don’t work, we can restart them and increases pressure appropriately. Don’t see the rollers as follow-up wheels.
d. Improper upper puncher
Puncher with different code will have different length. Mixed use of upper punchers can cause tablets to be loose. Unqualified punchers can be another cause for loose tablets. Before mould installation, please check the mould over and over again and change the mould which is unqualified.
2) Material
a. High roughness of material and elastic crude fiber in granules
Loose tablets will be produced because of high roughness and elastic crude fiber of granules. It’s better to process material to proper fineness. The material can also be screened again for higher fineness if the previous machines are not easily controlled.
b. Low dosage of adhesive or dry granules
Technical investigation should be carried out to determine reasonable adhesive dosage range.
c. Nonuniform granule size distribution and poor fluidity
Moderate granule size range can be determined by the result of technical investigation.
