Zuurman K, Van der Voort Maarschalk K, Bolhuis G K
Groningen Institute for Drug Studies (GIDS), Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Ant. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
Int J Pharm. 1999 Mar 1;179(1):107-15. doi: 10.1016/s0378-5173(98)00389-5.
The negative effect of magnesium stearate on tablet strength is widely known. This strength reduction is always considered to be the result of reduction of interparticle bonding. It is also known that interparticle bonding affects relaxation of tablets. Relaxation increases with decreasing bonding. Microcrystalline cellulose is an example of a material with a high lubricant sensitivity, which effect is caused by its plastic deformation behavior during compression. This paper shows for microcrystalline cellulose that the porosity under pressure was equal for unlubricated tablets and for tablets containing 0.5% magnesium stearate. This points to equal densification properties. The lubricated tablets show, however, a much larger relaxation than the tablets without magnesium stearate. This difference can be ascribed to the reduction of interparticle bonding by the lubricant, because a strong interparticle bonding counteracts tablet relaxation. In contrast to microcrystalline cellulose, aggregated gamma-sorbitol (Karion Instant) has a low lubricant sensitivity. Both porosity under pressure and tablet relaxation were found to be equal for lubricated and unlubricated sorbitol tablets. This phenomenon is caused by the particle structure of gamma-sorbitol. During compression, a lubricant film will be destroyed by fragmentation of the sorbitol aggregates. For this reason, magnesium stearate will hardly affect the interparticle bonding between sorbitol particles and hence have only a small or no effect on tablet relaxation.
硬脂酸镁对片剂强度的负面影响是广为人知的。这种强度降低一直被认为是颗粒间结合力降低的结果。还已知颗粒间结合力会影响片剂的松弛。随着结合力降低，松弛增加。微晶纤维素是一种对润滑剂敏感性高的材料的例子，这种影响是由其在压缩过程中的塑性变形行为引起的。本文表明，对于微晶纤维素，未润滑片剂和含有0.5%硬脂酸镁的片剂在压力下的孔隙率相等。这表明致密化特性相同。然而，润滑片剂的松弛比不含硬脂酸镁的片剂大得多。这种差异可归因于润滑剂导致的颗粒间结合力降低，因为强颗粒间结合力会抵消片剂的松弛。与微晶纤维素不同，聚集体γ-山梨醇（卡里翁速溶型）对润滑剂的敏感性较低。已发现润滑和未润滑的山梨醇片剂在压力下的孔隙率和片剂松弛均相等。这种现象是由γ-山梨醇的颗粒结构引起的。在压缩过程中，山梨醇聚集体的破碎会破坏润滑膜。因此，硬脂酸镁几乎不会影响山梨醇颗粒之间的颗粒间结合力，因此对片剂松弛的影响很小或没有影响。
