Accelerated stability testing of bioproducts: attractions and pitfalls

Accelerated testing is widely used for the prediction of storage stability and quality, and for the estimation of shelf-lives and 'safe' storage temperatures of labile products. In the food, pharmaceutical and bioindustries, products are stressed by testing at high temperatures. The results are then extrapolated to 'normal' storage conditions. Many such products exist as amorphous solids and are therefore thermodynamically unstable. During accelerated testing, dramatic and sudden physical and/or chemical changes can occur within such products, rendering extrapolation misleading. A knowledge of possible physical changes during heating enables accelerated testing to be performed with confidence.