Scuffing in Tablet Coating

With more and more washing of the pan and the use of cleaning materials and drying and also with the old age and too much using the machine, the stainless steel of the pan is affected and may interact with the tablets . Now some brands of coating machines have begun to fix this problem and manufacture anti-scuffing machines using very good types of stainless steel. With baffles design in the sides of the pan to help the tablets move properly.

 

What is the description of the problem?

It is friction and interaction between the tablets. and the coating pan wall, which leads to the appearance of gray stien on the surface of the tablets. And This problem occurs in light-colored tablets and with high-density tablets .

 

Causes and Solutions

1: When the batch size is small compared to the capacity of the pan. 

Solution: Increase the batch size inside the machine.

 

2: The pan speed is very low.

Solution: Increase the pan speed. 

 

3: A large percentage of titanium dioxide in the coating solution.

Solution: Reduce the percentage of titanium in the solution.

 

4: The problem appears when the high tablets bed temperature.

Solution: Reduce the temperature of the tablets.

 

5: When the distance between the guns and the tablet bed is too far and therefore the solution does not reach the tablets, the temperature of the tablet will increased.

Solution: Reduce the distance between guns and tablets.

 

6: When the process time is long. 

Solution: Reduce the time of the coating process.

 

7: Spray rate is very low.

Solution: increase the spray rate.

 

Some tips to avoid this problem:

1: Maintain the drum continuously, make sure there are no scratches, and make sure it is cleaned well.

2: There must be a ratio and proportionality between the three coating factors (drum speed / spraying / temperature).

3: Spray the drum by the coating solution before placing the tablets to isolate between the pan and the tablets . This method is the common way to avoid the problem, but it has the disadvantage of increasing the cost of using more solution.

 

Read also:

• CPP and CQA of Different Stages of Drug Product Manufacturing
• Common Tablet Manufacturing Defects in Pharma