ASSESSMENT OF ADHESION AND AUTOADHESION FORCES BETWEEN PARTICLES AND SURFACES .1. THE INVESTIGATION OF AUTOADHESION PHENOMENA OF SALMETEROLXINAFOATE AND LACTOSE MONOHYDRATE PARTICLES USING COMPACTED POWDER SURFACES
F. Podczeck et al., ASSESSMENT OF ADHESION AND AUTOADHESION FORCES BETWEEN PARTICLES AND SURFACES .1. THE INVESTIGATION OF AUTOADHESION PHENOMENA OF SALMETEROLXINAFOATE AND LACTOSE MONOHYDRATE PARTICLES USING COMPACTED POWDER SURFACES, Journal of adhesion science and technology, 8(12), 1994, pp. 1459-1472
A centrifuge technique has been used to investigate the autoadhesion f
orce between particles and a plane surface of the same material compac
ted into a disk, which is resistant to the centrifugal force. When mea
sured by profilemetry, these compact surfaces are rougher than metal o
r plastic surfaces used in previous studies. This results in a change
of the detachment force distribution from a log-normal to a right-shif
ted distribution. The relationship between press-on force and median a
utoadhesion force depends on particle size, shape and particle surface
morphology of the powder particles autoadhered. The lower the autoadh
esion force, the greater the possibility that the substance can be use
d in a single-component powder application. The bulk properties of the
powders such as cohesiveness or free powder flow were found to be rel
ated to the autoadhesion force. Estimation of the distance between the
particles and surfaces has been made based on the Lifshitz-van der Wa
als constant derived from low frequency dielectric measurements. There
was a decrease in distance of separation with increase in press-on fo
rce for both sets of particles. The contact between angular lactose mo
nohydrate particles and a lactose monohydrate surface can be increased
by more than that between irregular or spherical salmeterol xinafoate
particles and their equivalent compact surface.