Eudragit NE 30 D aqueous dispersion is a commonly used coating material, which contains methacrylate copolymers as film-forming
agent and nonoxynol 100 as an endogenous emulsifier. The dissolution of the active ingredient from Eudragit NE-coated samples
during storage is known to undergo a change. The crystallization of the emulsifier agent can play an important role in this.
This polymer is not soluble in the gastrointestinal tract, but is permeable. Various parameters can influence the permeability
of this film, e.g. via the tensile properties of the film. Change in the film thickness can cause the stretching of the film
on a solid surface. Alterations in this physical parameter of the film were measured and the effects of different storage
conditions were evaluated. The free film was prepared by spraying onto teflon. The crystallization of nonoxynol was followed
via the changes in the DSC curve of the free film. A relationship was found between the film thickness and the crystallization
of nonoxynol. It was established that the different storage conditions influence these changes. The temperature and the air
humidity are important in this phenomenon. Lengthening of the storage time increased the difference in film thickness and
crystallisation of emulsifier.