3. Storage stability requirements

One aspect of encapsulation—which may seem trivial but is all too often overlooked in the scientific literature—is that a capsule must be able to retain the active ingredient within it, even during prolonged storage in the final product and often under demanding temperature conditions, such as three months at 50 °C. This stability requirement is unavoidable in commercial applications. While one might expect good performance from capsules containing freshly encapsulated fragrances, it is very common for this performance to decline rapidly within a few days! Unfortunately, there are countless publications that fail to mention this deficiency, even though it is so easy to demonstrate.

The main reasons why a scented capsule loses its effectiveness over time are:

• the disintegration of the capsule due to dissolution or degradation...