The objective of PDA Technical Report No. 53: Guidance for Industry: Stability Testing to Support Distribution of New Drug Products is to describe and justify the studies using scientific data and rationale necessary to determine an appropriate stability budget for a drug product. This is the first of seven categories, or pillars, of Good Distribution Practices (GDPs). PDA has provided general guidance on the first four pillars in Technical Report No. 52: Guidance for Good Distribution Practices for the Pharmaceutical Supply Chain, published in 2011. Technical Report No 53 focuses on four situations that should be considered during stability testing; these are: 1. Product Storage: Temperature is typically controlled and the risk of shock and vibration is expected to be minimal. 2. Manufacturing and distribution operations (road, sea, and/or air): Product is moved from one storage condition to another: temperature control may or may not be present. In addition to temperature stress, the risk of shock and vibration may be significant during distribution operations. 3. Product Use under many circumstances, including following reconstitution from powder or simply by end-users (practitioners and/or patients): There may be considerable variability in temperature control but the risk of shock and vibration is minimal. 4. Excursions: Temperature goes outside the recommended range for that segment of distribution or during controlled temperature storage of the product.