Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate

Here at Gamlen we are highlighting some of the fascinating and ground-breaking research that has been carried out by our customers in our Paper of the Month posts.

Poor lubrication is the cause of many tableting failures. The authors of our paper of the month have taken a novel approach to tackling this issue. They have successfully used a mechanofusion coating approach to lubricate ibuprofen powder with magnesium stearate. They then investigated the key CQAs of the final tablets, including using the Gamlen to measure lubricant efficacy

Figure 9. Ejection stress of prototype ibuprofen tablets (error bars represent SDs, n¼5).
  • A fine grade of ibuprofen was selected as the model drug for its cohesiveness
  • The dry powder coating (mechanofusion) method and the traditional low shear blending method were used to lubricate samples of the ibuprofen, and ibuprofen + PVP, with magnesium stearate
  • The dry powder coating method produced powders with improved flow properties
  • Gamlen data showed that the dry powder coated samples displayed lower ejection stresses, and therefore improved lubrication, compared to the blended samples
  • Dissolution studies showed that the dry powder coating lubrication method did not increase tablet dissolution times.


The authors have demonstrated that introducing a lubricant into a tableted formulation using a mechanofusion coating method can result in more effective lubrication and improved powder flow compared to the traditional blending approach.