The assessment of particle friction of a drug substance and a drug carrier substance

• DOI: 10.1007/bf01151531
• Publication Date: 2005-02-08T11:36:37Z
• Authors: F. Podczeck; J. M. Newton; M. B. James
• Keywords: Centrifuge; Particle (ecology)

The centrifuge technique, which has been previously used in adhesion experiments, has been modified for use in single particle friction studies. Both flat compacted surfaces and large single particles were used as substrate surfaces to allow assessment of drug-drug, drug-drug carrier and drug carrier-drug carrier friction forces. Particle size, particle shape and surface roughness were identified as main factors influencing the change from a static into a dynamic friction process and the division between friction due to adhesion and ploughing. The forces of adhesion and friction were found to be proportional to the reversible energy of adhesion. The ratio between the force of adhesion and the press-on force applied and the ratio between the force of friction and the press-on force can be related to the yield stress and the reduced Young's modulus of the materials in contact.