title: Effect of the Curvature of the Punches on the Shape of the Interface and the Delamination Tendency of Bilayer Tablets.
abstract: Bilayer tablets are of special interest in the pharmaceutical industry. The main problem during their manufacturing is the occurrence of delamination during or after the ejection from the die. This work studies the influence of using punches with a curvature on the interfacial strength and thus on the delamination tendency of bilayer tablets. Bilayer tablets were produced with a compaction simulator using different flat and concave punches with different radii of curvature. The main compaction pressure was kept constant but the tamping force was varied. Two bilayer model systems were studied. The interfacial strength was determined using a previously described indentation test. The factors studied were analyzed for statistical significance with respect to the responses. The curvature of the interface was found to be higher when the curvature of the punch and the tamping force increased. Breaking tests then demonstrated that, for bilayer tablets obtained using the same compression parameters, the interfacial strength was lower when the curvature of the interface increased. As a consequence, when producing bilayer tablets with concave punches, it is important to choose properly the tableting parameters in order to have an interface between the layers as flat as possible to avoid delamination issues.
authors.affiliation: University of Bordeaux, CNRS, Bordeaux INP, Arts et Métiers ParisTech, I2M, UMR 5295, 146 rue Léo Saignat, Bordeaux F-33000, France.
authors.forename: Luca
authors.initials: L
authors.lastname: Castrati
authors.affiliation: University of Bordeaux, CNRS, Bordeaux INP, Arts et Métiers ParisTech, I2M, UMR 5295, 146 rue Léo Saignat, Bordeaux F-33000, France. Electronic address: vincent.mazel@u-bordeaux.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Mazel
authors.affiliation: University of Bordeaux, CNRS, Bordeaux INP, Arts et Métiers ParisTech, I2M, UMR 5295, 146 rue Léo Saignat, Bordeaux F-33000, France.
authors.forename: Harona
authors.initials: H
authors.lastname: Diarra
authors.affiliation: University of Bordeaux, CNRS, Bordeaux INP, Arts et Métiers ParisTech, I2M, UMR 5295, 146 rue Léo Saignat, Bordeaux F-33000, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Busignies
authors.affiliation: University of Bordeaux, CNRS, Bordeaux INP, Arts et Métiers ParisTech, I2M, UMR 5295, 146 rue Léo Saignat, Bordeaux F-33000, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Tchoreloff
mesh_terms: D019245:Compressive Strength; D005079:Excipients / Q000032:analysis / Q000138:chemical synthesis; D013314:Stress, Mechanical; D013499:Surface Properties; D013607:Tablets / Q000032:analysis / Q000138:chemical synthesis*; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D005079:Excipients; D013607:Tablets
keywords: bilayer; compaction; mechanical properties; tablet; tableting