This work deals with the preparation and characterisation of poly(n-butyl-2-cyanacrylate) nanocapsules. The mean applications of these particles are their use as drug-carriers, in order to increase the efficiency and to reduce the side effects of pharmaceuticals. By coupling size exclusion chromatography with multi angle laser light scattering a procedure for size determination of nanocapsules is developed. In this connection the analysis of the light scattering data is discussed in detail. Concerning the optimization of the capsule preparation, the influences of different parameters (components concentration, type of stirrer and sample preparation) on the size and size distribution of the nanocapsules are determined. Regarding the characterisation of the polymer cover, the wall thickness as well as the molecular weight distribution of the polymer are analysed. Further, the capsule wall is simulated by a planar polymer film. Rheologic and H-NMR investigations on this film allow to observe the kinetics of wall formation. The rheologic measurements give additional information about the viscoelastic properties and the cross linkage of the polymer.