Hygroscopicity: Hygroscopicity refers to the ability of a substance to absorb moisture from the environment.
In the context of pharmaceuticals, understanding and classifying the hygroscopicity of drug substances and excipients is crucial for ensuring stability, quality, and efficacy throughout the product's shelf life.
Classification of hygroscopicity In European pharmacopeia, hygroscopicity is described by four different classes after being stored at 25°C at relative humidity of 80% for 24 hours.
• Non-hygroscopic: After abovementioned storage condition, if overall increase in weight is less than or equal to 0.12% w/w.
• Slightly hygroscopic: After abovementioned storage condition, if overall increase in weight is greater or equal to 0.2% but less than 2% w/w.
• Hygroscopic: After abovementioned storage condition, if overall increase in weight is greater or equal to 2% but less than 15% w/w.
• Very hygroscopic: After abovementioned storage condition, if overall increase in weight is greater than 15% w/w