Evaluation of the suitability of various lubricants for direct compaction of sorbitol tablet formulations
Abstract
There is an increasing interest in polyols such as sorbitol in pharmaceutical tablet formulations due to their sweet taste but reduced calorie content and noncariogenic characteristics. Sorbitol is a common tableting excipient and plays a major role in the manufacture of chewable and sublingual tablets. One limitation of sorbitol as tableting excipient is that its hygroscopic nature may cause pronounced friction as well as sticking to the punch surfaces. Therefore, the aim of the present study was to evaluate the suitability of various lubricants for reduction of friction and prevention of sticking during compaction of sorbitol-containing tablets. The efficiency of the most commonly used lubricant magnesium stearate was compared to that of sodium stearyl fumarate (Pruv®), microprilled poloxamer 407 (Lutrol® micro 127) and PEG 4000. Compaction studies were performed using an eccentric tablet press as well as a rotary die tablet press. In addition to the compaction properties, the effect of the investigated lubricants on the tablet properties was evaluated.
Considering both the lubricant efficiency and the influence on tablet properties among the investigated lubricants, Pruv® turned out to be most suitable for compaction of the investigated sorbitol tablet formulations. However, the best overall lubricant performance accompanied by excellent tablet properties was observed with a mixture (1:1) of magnesium stearate and Pruv®, indicating a synergistic effect of both lubricants.