Quality control is an important aspect in tablet compression process or pill press. However, you can only achieve perfect tablet production once you know the possible defects, their causes and possible remedies.
With this information, you can buy the right equipment to ensure perfect tablet compression process.
To help your factory reduce possible wastages, we will take you through all possible defects in tablet compression process.
Common Types of Tablet Defects
Let’s explore every defect you may encounter in compressed tablets, common causes and possible solutions.
1. Capping
This occurs when the top or bottom component of the tablet separates from the main frame.
Cause
- Excess dust in the granules limits compression, leading to trapped air, which results in capping.
- Reduced moisture content causes ineffective bonding, as the granules that are too dry lack the plasticity required.
- Air trapped during the compression procedure will result in a tablet with a weakened structure, leading to the top or bottom to separate
- Too much or too little compression force can result in capping occurring.
- Another cause of capping in a tablet is inconsistent granules, which result in varying particle sizes as well as poor flow.
Remedy
- This problem can be solved using a 100- 200 mesh screen to elevate air flow
- You can use controlled humidification, which allows you to adjust the tablet’s moisture content. You can also incorporate a more binding solution to elevate cohesion.
- Pre-compression procedures can be carried out to eliminate any trapped air. This is done by adjusting the force and speed of compression. You can also use a tapered die to help air flow.
- This problem can be remedied by using the correct force for both the pre-compression and main compression procedures.
- You need to refine binder distribution to ensure that the granules produced are uniform
2. Lamination
This is a defect that causes the tablet to split horizontally into two or more layers, diminishing the integrity of the tablet. This defect can occur during the compression procedure or after the process is complete.
Cause of laminations
- When air is trapped between the granules or the cavity of the die during the compression process, it compromises the integrity of the tablet, resulting in the horizontal layers separating.
- Excess fine particles in the granules inhibit proper binding and may result in this defect.
- Very dry or very moist granules may result in lamination as excess moisture hinders binding, while dry granules have limited cohesion.
- Improper use of the binder limits particle bonding, which leads to this defect.
- Using excessive compression force as well as quick decompression can result in internal stress, causing the layers to separate
- If you use faulty tools or input the incorrect machine setting. It results in uneven pressure, which results in lamination.
- Using the wrong type of lubricant or using the wrong amount of lubricant can result in the separation of the layers.
Remedy of lamination
- You can incorporate pre-compression steps to facilitate air flow.
- Optimizing the granulation process helps to prevent varying granule sizes by removing excess fine granules, optimizing moisture content.
- You should appropriately adjust the binding agent as well as the right lubricant to suit your formula by using the correct type and amount of both these products.
- Adjust the necessary settings to prevent fast decompression as well as us of excessive force.
- You should conduct regular tool maintenance will ensure that the tools remain optimally functioning.
- Utilizing tapered dies can aid in minimizing peripheral relaxation, thereby reducing the risk of this defect.
3. Sticking
This defect involves the granulated powder sticking to the surface of the die or punch, which produces deformed tablets that have poor quality. This increases the production period while resulting in a loss of granulated powder.
Causes
- Elevated moisture in the granules as a result of improper drying
- Using the wrong type of lubricant or using the wrong quantity will hinder the friction between the granules and the tools.
- Utilizing excess binder will make the resulting product sticky
- Some ingredients are hygroscopic, meaning they absorb moisture from the environment.
- Using oily or waxy raw materials will result in a sticky powder
- The quality of your granules also plays a role, as granules that are too soft and uneven have a higher chance of being sticky.
- The condition of your tools also influences this defect, as rough, uneven surfaces increase the risk of sticking
- Compression force and speed can lead to sticking
Remedies
- You should ensure that the granules are properly dried according to the requirements of your formula. Always use the right granulation machine.
- Increase the quantity of the right kind of lubricant
- Adjust the amount of binder to better suit your formula
- You can carry out the compression under controlled humidity, more so if you are using hygroscopic materials
- You also need to maximize the efficiency of your granulation process to ensure uniform granules that do not stick.
- Appropriately adjust the machine setting to ensure that the right amount of force and speed is used
4. Picking
This defect occurs when a limited area of the surface of the tablet is torn off, as the portion remains stuck to the face of the punch. This defect mainly affects the areas that are uneven due to the letters or logos.
Causes
- Granules with excess moisture content or those that are hygroscopic heighten the stickiness, leading to picking
- Insufficient lubrication leads to inadequate reduction of friction between the tools and the granules.
- Some select binders cause the granules to adhere more to surfaces.
- Intricate embossing and engravings that are deep create an uneven surface, which can lead to this defect.
- Failure to properly dry the granules will lead to this defect.
- Excessive compression force can also cause this defect.
Remedies for Picking
- Using the appropriate amount and type of lubricant helps to prevent this defect.
- It is important to ensure that the granules have been properly dried.
- Humidity-controlled environments help eliminate any excess moisture, especially for hygroscopic granules.
- Adjust the parameters of your formula by changing the type or quantity of binder you use.
- You can enhance the flow and stickiness of the grains by refining the size of the granules.
- Regularly cleaning and maintaining the tool, such as the punch, helps prevent picking caused by rough surfaces.
- Adjust the compression settings for optimization of force and speed.
5. Binding
This occurs when the tablet adheres to the wall of the die during compression as well as ejection. Tablets with this defect appear rough and may have damaged sides, resulting in broken tablets.
Causes
- Lack of enough lubricant, as well as the use of the wrong type of lubricant
- The moisture content of the granules, that is, whether they are too wet or too dry.
- Granules that are not uniform will lead to sticking due to inconsistent filling.
- A rough or worn-out die can result in binding due to elevated resistance from the textured surfaces.
- Excess compression force and speed can result in difficulty during ejection
- Using incorrect settings, such as the wrong ejection speed or the takeoff blades being misaligned, can lead to this defect.
Remedies
- Ensure you use the most suitable type of lubricant in the right quantity.
- The granules should be optimally dried
- The granulation process should result in uniform granules that can be properly pressed.
- Ensure uniform, free-flowing granules with good compressibility.
- Appropriately adjust the compression forces to prevent too much compaction.
- Ensure that the machine has been accurately set up.
- The die, as well as other tools, should undergo regular maintenance
6. Mottling
This is when there is uneven color distribution on the surface of the tablet. The defects result in the tablets that have dark patches or blotches, therefore reducing the overall quality of the tablet.
Causes
- Poor blending of the colors or using excipients with no color and drugs with color
- Movement of the dye during the granulation process is another cause.
- If you do not properly mix the dye, especially if you are using the direct compression method or color blinders
- Uneven moisture distribution across the tables can lead to uneven coloring
- The interaction of the various chemicals used in the formula can lead to discoloration.
- Uneven granule sizes can result in a non-uniform coloring
Remedy
- Thoroughly blend the colorants
- Ensure that the ingredients used in your formula are compatible
- Ensure that their granules are all properly dried to prevent uneven moisture
- Control and monitor moisture content during granulation and drying.
- Utilizing high-quality colorants that can be properly dispersed
7. Flashing
This defect features a thin and unintentional burr around the perimeter of the tablet. It is usually formed during the compression process and lowers the quality of the tablet, as well as compromising its integrity.
Causes
- Overfilled die cavity, causing the excess material to be pushed out.
- Misaligned punches, as well as those that have been worn, can allow bits of the material in the cavity to escape.
- Inadequate, uneven, or excessive compression forces can result in this defect
- Uneven die filling may result in the overfilled sections spilling out.
Remedy
- Fill the required amount of material in the die
- Ensure that the tools and dies have been properly aligned
- Use the recommended compression setting to prevent uneven distribution.
- Ensure that the material is uniformly distributed in the die cavity
8. Chipping
This defect features breaking or loss of minute pieces, typically from the tablet’s edges. This defect occurs after compression, during procedures such as coating or handling. The defect affects the integrity of the table as well as its appearance.
Causes
- Excessively dried powder loses its plasticity, which increases the risk of this defect occurring
- If the tablet is too soft, the edges can fall off under mechanical stress.
- Using poor-quality tools or tools that are worn results in an uneven pressure distribution
- Using inadequate lubrication increases friction
- Excessive and inadequate compression force.
- The design of your tablet influences this defect, as sharp-edged tablets are more prone to chipping as opposed to rounded tablets.
- Machine settings such as misaligned sweep-off blades, elevated ejection take-off plates, as well as wrong assembly of the knock-off plates.
Remedies
- Accurately adjust the moisture content of your formula for enhanced plasticity.
- You should adjust the compression setting to ensure that the required force is dispensed.
- Ensure you utilize the right type as well as the correct amount of lubrication.
- It is important to regularly and thoroughly carry out maintenance practices such as polishing, cleaning, or replacing worn-out components.
- Modify your formula by adjusting the concentration of the binders as well as the granulation process.
9. Cracking
This defect is characterized by the presence of small splits, usually occurring at the top or bottom of the surface. This defect can occur during compression, handling, as well as coating.
Causes
- Granules that are larger will result in this defect
- Overly dried powder lacks the plasticity required and could result in the surfaces cracking.
- Disproportionate use of binders minimizes particle adhesion, resulting in cracks.
- Use of too much compression force can lead to the tablets getting fractured.
- Improperly setting up your machine can lead to issues arising during the ejection step and may result in cracks on the surface.
Remedies
- Minimize the size of the particles to reduce internal stresses
- Adjust the moisture content and binder content to better suit your formula
- The compression force and speed are used to minimize pressure
- Optimally dry the granules to prevent them from being too brittle
- Regularly maintain the tools and machinery that are used in the production process.
- Adjust the formula and choose suitable ingredients that are compatible.
10. Double Impression
This defect presents as identical impressions of the surface of the tablet when it should be a single marking. The punch impression gets duplicated, leading to the double markings.
Causes
- Punches that are at a lower level or have free rotation
- Rounded punches are more likely to leave a double imprint.
- If your punch features embossed digits, monograms, or a bisect line, tendare at a higher risk of producing a double print.
- Absence of anti-rotation guards as well as keyways can lead to this defect.
- Wrong alignment or fit can result in tablets with this defect.
Remedies
- Incorporate keyways as well as side locks to prevent the punch from moving
- Introduce anti-rotation mechanisms to prevent to limit the movement of the
- Ensure that you regularly maintain the punch, dies, and all other tools.
- Control the speed of the machine setting to what is recommended for your formula.
- Ensure that the machines and tools have been properly set up and aligned.
11. Hardness Variation
This defect influences the mechanical strength of the tablet, resulting in tablets that are too hard or too soft. This defect influences the tablet’s dissolution a well as its disintegration time.
Causes
- Improperly blending the ingredients in your formula can cause uneven distribution.
- Non-uniform granules cause uneven compression, resulting in a variation in the hardness.
- Using an incorrect ratio will result in the wrong proportions, causing uneven distribution.
- If there is a variability in the compression force can cause a difference in the hardness.
- Improper drying can cause varying moisture levels, leading to varying hardness
- Inadequate lubrication can also increase the risk of this defect
- Wrong alignment, as well as worn-out components, can cause a variation in force distribution.
Remedy
- Thoroughly blend the ingredients to create a uniform mixture
- Use granulation procedures that will produce granules of the same size.
- Ensure that you set accurate compression parameters to ensure consistent force is output.
- You can adjust the ratios of your formula to the hardness.
- Ensure that the granules undergo a standard drying procedure to ensure that there is uniform moisture content.
- Ensure that you conduct thorough and regular tool and machine maintenance.
- Adjust your lubricant accordingly
12. Weight Variation
This defect involves tables with varying weights. This is a problem as most tablets contain a single dose; varying weight means that there are tablets with less than the required dosage or more than the required dosage.
Causes
- Limited flow of powder can result in varying amounts filled in the die
- Inconsistency in the filling of the die cavity can also contribute to this defect
- If your machines have the wrong calibration.
- Ingredients and binders with varying weights can result in a variation in the weight.
- The environmental conditions, such as elevated humidity and static charges, can lead to this defect.
Remedies
- You can employ flow enhancers to improve the flow of the particles
- Accurately calibrate your machine settings so that it operates under the recommended parameters
- You can use feeding mechanisms with vibrations to optimize the filling process.
- Produce the tablets under controlled environmental conditions.
- Upgrade your granulation technique to get uniform granules.
13. Disintegration Time Too Long
In some cases, a tablet may take longer to disintegrate, which delays the medicinal properties from taking effect immediately. This reduces the overall efficiency of the tablet.
Causes
- The type as well as the amount of disintegrant that you incorporate into your formula
- Elevated or inadequate compaction pressure
- Reducing porosity can also lengthen the disintegration period.
- Using a lot of binder or hydrophobic excipients limits the tablet’s ability to absorb moisture.
Remedies
- Use the correct type and quantity best suited for your formula
- Elevate the porosity of the tablet by adjusting the formula as required.
- Elevate your granulation and drying techniques to better control the sizes of the particles produced as well as the moisture content
- Optimize the machine settings to ensure that the required compression force is applied
14. Black Spots/Stains
These are dark colored spots that appear on the surface of the tablet. This negatively influences the appearance of the tablet and therefore minimizes its quality
Causes
- Contamination from the lubricant used on tools
- Elevated friction or generated heat can result in this defect
- Unequal distribution of the ingredients
- Presence of impurities and other contaminants.
- Improper coating solution
- Incorrect machine setup resulting in misaligned tools
Remedies
- Ensure that all your ingredients are properly and uniformly mixed
- Use materials that are of a higher quality and do not contain any contaminants
- Properly and regularly maintain your tools and equipment
- Ensure that you properly set and accurately align your tools
- Optimize your granulation techniques to prevent varying grain sizes
- Ensure that the raw material as well as the finished products are stored in ideal conditions
- Ensure that the lubricants incorporated are thoroughly mixed.
- Utilize the recommended compression parameters
- Properly maintain the equipment used to spray the coating
15. Bisected/Score Line Issues
These are lines that are typically part of the design of the tablet. These lines can increase the chances of the tablet splitting following the line. This not only compromised the content of the tablet but its integrity is also affected.
Causes
- Nonuniform slitting, which results in a variation b the tablet’s weight
- Inadequate mechanical strength to withstand any handling
- The type of line used can directly influence this defect
- The design of your punch and die can compromise the integrity of the tablet, causing this defect.
- Improper handling of the tablet during the tablet
Remedy
- Ensure you properly design your tablet, taking the intricacy of the design into account during splitting
- Properly and regularly maintain your tools and equipment.
- Apply the use of tools that are more advanced by utilizing the pressure sensitivity to ensure even splitting
- Adjust your formula to elevate the integrity and mechanical strength of the final product
- Regulate control thickness as well as the hardness of the tablet
- Employ skilled labor to properly handle the tablets
- Adhere to the set guidelines for the manufacturing of tablets
16. Layer Separation
This defect presents as the separation of the various layers that the tablet is comprised of. This minimizes the mechanical strength as well as affecting the profile of the tablet.
Causes
- Inadequate compression force can result in ineffective adhesion of the various layers
- When air gets trapped in between the granules, this defect can occur
- Your active ingredients could be incompatible, preventing the powder from sticking together
- Uneven moisture distribution across the table
- Varying levels of elasticity of the various ingredients can result in this defect
Remedies
- Use the recommended compression parameters by adjusting both the pre- and main compression pressures to ensure a uniform bond
- Minimise trapped air by adjusting the compression force and speed accordingly to facilitate air flow
- You should consider utilizing excipients that enhance the interlayer bond
- Ensure that the Active Pharmaceutical ingredients used in your formula are compatible.
- Control the weight and thickness of the granule to ensure that there is uniform filling
- Maintain consistent layer weight and thickness for even compression pressure distribution.
- You need to manage the storage and production conditions, such as controlling temperature and humidity.
17. Cratering
These are small depressions that form on the top coating of the tablet. These holes typically expose the core of the tablet, impacting both the quality and appearance of the tablet.
Causes
- The coating liquid seeps into the core of the tablet
- Improper drying of the powder
- Overwetting with the coating solution
- Reduced drying temperatures inhibit proper drying.
- Incorrect hardness meaning tablets that are softer or harder than recommended
- Using an unsuitable coating formula
Remedy
- Minimize the rate of spray to avoid overwetting
- Use the recommended drying temperature and enhance air flow to ensure there is uniform drying
- You can adjust the formula of your coating to make it more suitable.
- You can either adjust the formula or the compression force to improve the hardness
- Have a seamless surface, as textured surfaces are more prone to this defect
- Use compatible binders and plasticizers to increase the integrity of the coating.
- Ensure that you have set the correct parameters on your machines and continuously monitor to prevent any system errors.
Causes
- Elevated core temperatures can result in this effect
- Clumping of lubricants can lead to a portion of the tablet dissolving
- Improperly drying the tablet can lead to clumps of it falling off or shrinking, resulting in a pit.
- Excessively setting the surface during the coating process can result in portions of it sinking.
- Super disintegrant can lead to swelling, causing bits of the tablet to fall off.
- Not mixing your formula properly
- Exposure to elevated humidity in the environment.
- Misaligned tools, such as the spray gun.
- Using a miscalibrated machine
Remedy
- Maximize air flow to ensure that the granules are properly and uniformly dried
- Control the atomization and spray rate to prevent overwetting
- Use a suitable coating that is compatible with the tablet
- Ensure that you properly mix and blend your granules
- Avoid heat buildup to better manage the core temperature
- These processes should be carried out in a temperature and moisture-controlled environment.
- Carry out regular maintenance of the tools and machines.
18. Orange Peel Effect
This defect appears as rough textures coating similar to that of an orange peel. The textured appearance lowers the visual quality of the tablet.
Cause
- Using the wrong formula can cause tablets with minimal hardness to become textured on the surface.
- Tablets that are generally weaker can also develop this defect.
- Using coatings with elevated viscosity leads to poor distribution, causing the texture
- Using an improper type of binder or using the wrong quantity of the right kind of binder can result in this defect.
- High moisture content as a result of over-wetting can result in an uneven coating
- Insufficient air flow limits proper drying, leading to varying moisture content
- Improperly setting up and using the machines and tools
- Adverse environmental conditions such as elevated humidity
Remedies
- Ensure that you use the right formula for optimal hardness
- Use an accurate solvent-to-solid ratio to ensure that there is low viscosity
- Minimize the spraying rate to prevent overwetting.
- Ensure that the processes are carried out in a controlled environment with a controlled humidity level.
- Ensure that you have properly set up your machine and tools.
Conclusion
These tablets defects are mainly due to material preparation problems, not following the right compression machine or choosing inefficient equipment.
With this information, we believe your factory can optimize the tablet compression process. We have highly effective tablet press machines and quality control equipment.
