The water activity of an oral solid dose (OSD) product is changing constantly from when the pill, tablet, or capsule is first placed into its primary package and then throughout its entire shelf life when exposed to varying relative humidity and temperature conditions. As the humidity inside the primary package increases, the water activity of the product increases. It is water activity measurements, not total water content, that correlate to critical product quality attributes. Monitoring water activity throughout the product life cycle is important to control critical quality attributes such as microorganism growth, product degradation, product dissolution and product hardness or friability. Long term stability testing is required to prove that the product will maintain its potency, purity, and efficacy for its entire shelf life.
Explore the impact of water activity on the potency, purity and bioavailability of OSD products. Learn more about how USP<922> Water Activity impacts your primary packing selection and how laser-based headspace analysis has proven to be the optimum approach for performing water activity measurements of non-sterile pharmaceutical products.