title: Tensile and shear methods for measuring strength of bilayer tablets.
abstract: Both shear and tensile measurement methods have been used to quantify interfacial bonding strength of bilayer tablets. The shear method is more convenient to perform, but reproducible strength data requires careful control of the placement of tablet and contact point for shear force application. Moreover, data obtained from the shear method depend on the orientation of the bilayer tablet. Although more time-consuming to perform, the tensile method yields data that are straightforward to interpret. Thus, the tensile method is preferred in fundamental bilayer tableting research to minimize ambiguity in data interpretation. Using both shear and tensile methods, we measured the mechanical strength of bilayer tablets made of several different layer combinations of lactose and microcrystalline cellulose. We observed a good correlation between strength obtained by the tensile method and carefully conducted shear method. This suggests that the shear method may be used for routine quality test of bilayer tablets during manufacturing because of its speed and convenience, provided a protocol for careful control of the placement of the tablet interface, tablet orientation, and blade is implemented.
authors.affiliation: Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-127B Weaver-Densford Hall, 308 Harvard Street S.E., Minneapolis, MN 55455, USA.
authors.forename: Shao-Yu
authors.initials: SY
authors.lastname: Chang
authors.affiliation: DFE Pharma, 61 South Paramus Road, Suite 535, Paramus, NJ 07652, USA.
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Li
authors.affiliation: Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-127B Weaver-Densford Hall, 308 Harvard Street S.E., Minneapolis, MN 55455, USA. Electronic address: sunx0053@umn.edu.
authors.forename: Changquan Calvin
authors.initials: CC
authors.lastname: Sun
mesh_terms: D002482:Cellulose / Q000737:chemistry; D005079:Excipients / Q000737:chemistry; D007785:Lactose / Q000737:chemistry; D013314:Stress, Mechanical; D013607:Tablets / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods*; D013718:Tensile Strength
chemical_list: D005079:Excipients; D013607:Tablets; D002482:Cellulose; D007785:Lactose; C109691:microcrystalline cellulose
keywords: Bilayer; Lactose; Mechanical properties; Microcrystalline cellulose; Shear; Tablet; Tensile