Evaluation of Cocoa Butter as Potential Lubricant for Coprocessing in Pharmaceutical Tablets

Abstract

The lubricant activity of cocoa butter coprocessed with magnesium stearate plus talc (CMT) was compared with magnesium stearate plus talc (MT) using flow and compressional characteristics of paracetamol granules and mechanical properties of their tablets as assessment parameters. The flow of the granules quantified as Hausner's ratio, Carr's index, and angle of repose showed that CMT has a higher ability than MT to reduce densification of granules due to vibration. Compressional characteristics analyzed using density measurements and the Heckel and Kawakita plots revealed that CMT did not facilitate the increase in the densification of the granules during the filling and at low pressures, D_b. Also, CMT reduced the plastic deformation of the granules measured by the P_y-yield pressure at onset of plastic deformation and P_k-yield pressure of deformation under compression. The mechanical properties determined by the tensile strength, T, and brittle fracture index, BFI, of the tablets produced were affected by CMT. The T and BFI of tablets with CMT were lower than those of MT. The results suggest that though CMT lowered the plasticity of the granules, it improved their flow rate and assisted in producing tablets with fewer tendencies to cap or laminate. This work concluded that cocoa butter, an inexpensive and easily available lipid, is an effective and viable lubricant that can be co-processed with magnesium stearate/talc mixture for an efficient lubrication of granules and may be useful in reducing lamination and capping in formulations that are susceptible to these 2 defects of tablets.

Keywords:

• cocoa butter
• magnesium stearate
• Heckel plot
• Kawakita plot
• tensile strength
• brittle fracture index