Capping and Lamination are common tablet problems during compression where tablet separates in laminar fashion. 

Capping is partial or complete separation of top or bottom crowns of tablet main body. Where lamination is separation of a tablet into two or more distinct layers. Friability test can be used to reveal these problems. 


Reasons

  • Excessive fine powder
  • Over compression
  • Air entrapment
  • Low or very high moisture
  • Inappropriate powder & granules ratio
  • Excessive pre compression pressure
  • The problem stems from improper tablet compression, but it may not reveal itself until you start coating. How you operate the coating system, however, can exacerbate the problem.


Remedy

  • Don’t over compress
  • Check for proper machine setting, machine tooling
  • Adjust the tablet scraper properly (to tablet take off)
  • Lower punch can be set 0.1-0.2 mm above from the die surface
  • Verify the LOD
  • Increase dwell time (the duration of the closest time of two punches) by decreasing tablet presses speed
  • Avoid air entrapment 
  • Challenge the granulation (inadequate binder, poor blending, powder segregation, over mixing & poor flow)
  • Be careful not to over-dry the tablets in the preheating stage of coating. That can make the tablets brittle and promote capping.


Difference between Capping and Lamination

  • Separation in single layer top or bottom
  • Separation into multilayer (two or three)

  • Air entrapment, inappropriate powder & granules ratio are root causes of capping
  • Over compression, excessive fine powder are main causes of lamination