Evaluation of the suitability of various lubricants for direct compaction of sorbitol tablet formulations

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

Evaluation of the suitability of various lubricants for direct compaction of sorbitol tablet formulations

There is an increasing interest in using polyols, such as sorbitol, in pharmaceutical tablet formulations due to their sweet taste and 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 a 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 reducing friction and preventing sticking during the 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 both an eccentric tablet press and a rotary tablet press. In addition to their 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 of the investigated lubricants, Pruv® was found 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 synergism between these lubricants

Investigation of the formation process of two piracetam cocrystals during grinding

Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained