Analytical approach for lubricant characterization of excipients using the surface replication method.

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.

In this paper the authors investigate methods of evaluating tablet binding. Binding, also called die-friction, can be caused by powder adhesion to the die wall, and damages the sides of the tablet. The focus of their investigation is a surface replication method, BIND (Binding Identification for Net Detriment). They also generate ejection force and ejection energy data, using a Gamlen, and examine the usefulness of this data in evaluating tablet binding.

  • Raloxifene hydrochloride was selected as a model chemical which displays high adhesion, this was formulated with four different lubricants.
  • The BIND method involves the use of microscopy and image analysis software to calculate the powder adhesion density during compression and ejection.
  • BIND allowed qualitative and quantitative analysis of tablet binding properties.
  • The preparations without lubricants showed high powder adhesion density with the addition of lubricants significantly reducing this value.
  • An additional evaluation of three grades of magnesium stearate resulted in a two-fold difference between the highest and the lowest powder adhesion density values.
  • The BIND tablet binding evaluation results were consistent with visual observations but not with the ejection force measurements. However, the ejection energy values were consistent with the BIND and visual observation results.


The authors conclude that BIND is a promising method of evaluating tablet binding and provides useful information for lubricant optimisation. They also conclude that ejection energy rather than ejection force measurements are crucial to evaluating binding properties.