*Lipid and Polymeric Nanocapsules DOI: http://dx.doi.org/10.5772/intechopen.103906*

phenomena of nanocapsules are aggregation, precipitation, creaming, nanocapsule chemical degradation, and consequently, the reduction of drug content within the nanocapsule. All these phenomena can occur during the production process or after storage. Among the main reasons for them are inadequate steric or electrostatic stabilization, and the combination with external agents, such as oxygen, temperature, and ultraviolet radiation. In this way, the stability of nanocapsules is generally evaluated in terms of drug content, variations of zeta potential values, and average particle size as a function of time, pH, or temperature, using DLS or Zeta Potential techniques [23]. In some cases, the visual inspection of the colloidal suspension is also useful. On the other hand, some degradation products can be evaluated by chromatography or spectrometry [49].
