Long-term stability or degradation of drugs and pharmaceutical products: state-of-the-art

One of the fundamental parameters of drugs and pharmaceutical products is, in addition to their physiological effects, also their shelf-life. Even pharmaceuticals are subject to the effects of time, which gradually degrades and deteriorates them. This results in a reduction or even a serious change in the effects, or the development of toxicity. Therefore, the determination of the shelf-life of any drug or pharmaceutical product is of paramount importance. Unused drugs or pharmaceutical products after the expiry date have to be disposed of in a costly manner, which means financial losses and also imposes an unnecessary burden on the environment. There has recently been considerable discussion about the possible extension of the shelf-life of pharmaceuticals. The results of analyses of the historical remains of pharmaceuticals play an important role in this discussion. Therefore, an overview of recent results in this field is given here. In the first part, the review focuses on historical medicinal preparations (from antiquity to the early 19th century), which represent interesting, valuable, and often unique material for the study of the stability of medicinal substances over a long period (despite the uncertainty we have about their initial composition). The second part of the review gives an overview of articles on the stability of modern medicinal products, mostly already industrially produced.