During the tablet manufacturing process, some common tablet problems may inevitably appear, such as weight difference and insufficient hardness of tablets. These problems may be caused by material or equipment. In any case, they always can influence the quality of tablets. Hence, people should discover problems in time and deal with them in the light of specific conditions.
1. Loose tablet: Because of insufficient hardness, tablets are loosely powdered by vibration, named as loose piece.
-Inspection method: Place a tablet between the middle finger and the index finger, gently press it with your thumb to see if it is broken.
-Cause: The pressure is too small, the adhesive is not sticky enough or the amount is insufficient.
-Solution: Adjust the pressure, add appropriate adhesives, etc.
2. Split: A phenomenon in which a tablet is vibrated or placed, and a layer is peeled off from the waist or a layer is detached from the top.
-Inspection method: Take several tablets and shake them in a small bottle. No lobes should be produced. Or take 20-30 pieces in the palm of your hand. Combine the two hands and shake them several times to check if there are lobes.
-Cause: The elastic recovery of the tablet and the uneven pressure distribution, improper selection or insufficient dosage of the adhesive, excessive fine powder, excessive pressure, and the punch does not conform to the die ring.
– Solution: Change into the accessories with small elasticity and good plasticity, choose appropriate adhesive or increase the dosage, adjust the pressure, and replace the punch or the die.
3. Sticky punch: The surface of a tablet is stuck off a thin layer or a small portion, causing that the tablet surface is rough or concave. This phenomenon is known as sticking. (Punches engraved with text or horizontal lines are more prone to sticking.)
-Cause: Excessive water content, improper lubricant action, rough surface of the punch and too high humidity in the workplace.
-Solution: Control the water content, choose the right lubricant or increase the dosage, replace the punch, and control the relative humidity of the environment.
4. Slow disintegration: The tablet disintegration time limit exceeds the requirements of the Pharmacopoeia and the disintegration is slow.
-Cause: The tablet disintegration time limit exceeds the requirements of the Pharmacopoeia and the disintegration is slow.
-Solution: Appropriately increase the amount of disintegrant, reduce the amount of hydrophobic lubricant or change into hydrophilic lubricant, choose the appropriate binder and its amount, adjust the pressure and so on.
5. The weight difference among tablets exceed the limit: The weight difference among tablets exceed the allowable range specified by the Pharmacopoeia, known as weight difference of tablets.
-Cause: Uniform particle sizes, bad fluidity, inflexible lower punch, and too long material loading time.
-Solution: Control particle sizes evenly, replace the lower punch, and control the loading capacity between 1/3 and 2/3.
6. Discoloration or stain: It means that the change of color on the tablets surface or the appearance of stains with different colors cause that the appearance doesn’t meet the requirements.
-Cause: The particles are too hard; the mixture is uneven; it contacts with metal ions; the tablet press has polluted oil.
-Solution: Control the hardness of the particles; mix the original material and auxiliary material evenly; avoid contacting with the metal container; prevent leakage of oil from the tablet press.
7. Pitting: It means that there are many small pits producing on the surface of tablets
-Cause: The lubricant and adhesive are not used properly; the particles are wet and damp; the particle sizes are uneven; the coarse or fine powder is too much; the surface of the punch is rough or the lettering is too deep; the edges are angular; the machine is abnormally hot.
-Solution: Choose the right lubricant and binder and its dosage to avoid moisture in the particles; control the particle sizes evenly; replace the punch; avoid abnormal heating of the machine.