An experimental investigation of the effect of the amount of lubricant on tablet properties

Abstract

Background: Magnesium stearate (MgSt) is widely used as a lubricant in the production of tablets. However, the amount added to a formulation is often too high or it is poorly mixed, which can lead to the production of tablets whose properties are out of specifications. Method: The objective of this work was to investigate by means of a new method based on gamma-ray flux measurement and to study the impact of the amount of MgSt on the mass, thickness, hardness, friability, and disintegration time of tablets containing a 50 : 50 wt.% microcrystalline cellulose and spray-dried lactose pre-blend. Other blends were lubricated with sodium lauryl sulfate (SLS) to compare the performance of the two lubricants in equal amounts. Results: It was observed that, contrary to SLS, a greater amount of MgSt increased the variability of the tablet mass. The tablet hardness decreased with an increasing amount of MgSt, whereas it remained relatively unaffected by the presence of SLS. No solid conclusion could be drawn concerning the relationship between the lubricant concentration and the tablet friability. Conclusion: An amount of 0.25 wt.% MgSt and 0.75 wt.% SLS were found to be sufficient amounts of lubricants to obtain a proper compression.