Dispersion

Dispersion (from Latin dispergere: to disperse, spread), in chemistry and pharmacy designates a heterogeneous, i.e. non-uniform system of substances, a mixture of at least 2 substances which do not dissolve or only insignificantly dissolve in each other, and which also do not chemically combine with each other. In a dispersion, one or more substances (disperse phase) are finely distributed in another medium (external phase or dispersion medium).

The individual phases can usually be separated from each other again by simple physical methods (e.g. filtration, centrifugation) or they separate themselves (= sedimentation: typical behaviour of shaking mixtures).

If all particles in a dispersion are of the same size, a monodisperse system is present, and a heterodisperse system for different particle sizes.

Examples of disperse mixtures:

Cocoa (drink); Lotio alba aquosa (zinc shaking mixture);

1. Wolf G (2011) The problem of too many active ingredients. dermatologist 62: 78-79