Lubricant Efficiency of Magnesium Stearate in Direct Compressible Powder Mixtures Comprising Cellactose®80 and Pyridoxine Hydrochloride
Nilüfer YÜKSEL*°, Berna TÜRKMEN*, Aslıhan H. KURDOĞLU*, Berrin BAŞARAN*, Jülide ERKİN*, Tamer BAYKARA*
* Ankara University, Faculty of Pharmacy, Department of Pharmaceutical Technology, Tandogan, Ankara, Turkey

° Corresponding author E-mail: nyuksel@pharmacy.ankara.edu.tr

Summary

The purpose of the present study was to investigate lubricant efficiency of magnesium stearate in a model powder mixture of Cellactose®80 and pyridoxine HCL. A two-factor, three-level full factorial design (32) was created to observe the effects of lubricant on the flow properties, consolidation, and compressibility behaviors of the resulting powders and quality of the directly compressed tablets from the powders. The level of lubricant and the length of lubricant mix time were the independent factors.The dependent factors were the measured responses from the powder mixtures before compression such as angle of repose, flow rate, Carr’s index, Hausner index, and the intercept and mean yield pressure (Py) of Heckel equation. The measured responses from tablets were the percentage of friability, disintegration, and percent drug dissolved in 45 min. Nonlinear regression analysis indicated a good correlation (R2=0.999-0.844) between the measured responses and the independent factors. Lubricant amount had a statistically significant effect on
all the evaluated properties (p<0.05 or p<0.10). Lubrication time affected the angle of repose, the intercept of Heckel equation and, to a lesser extent, Py values of the powder mixtures. Optimum responses were obtained from the medium level of lubricant amount (2%) and medium level of lubricant mix time (6 min).

Key Words
Magnesium stearate, lubricant efficiency, direct compression, factorial design, pyridoxine HCl.