The requirement for stability studies conducted by manufacturing establishments is that they utilize real-time long-term tests. This method provides the most accurate reflection of how a drug product will perform throughout its intended shelf life under the actual conditions where it will be stored. Real-time long-term studies involve storing the product at its intended conditions and periodically testing it for various quality attributes over an extended period. This approach allows manufacturers to gather comprehensive data on how the product's quality, safety, and efficacy are maintained over time.
Accelerated studies, while useful for obtaining preliminary data, do not accurately predict long-term stability since they often involve subjecting products to conditions that are more extreme than typical storage conditions. Simulated time studies may provide some insights but are not standardized or as credible as real-time long-term tests. Short-term stability tests fail to account for the full extent of the product's stability under normal storage conditions. Therefore, real-time long-term testing stands as the gold standard for establishing the stability profile of pharmaceutical products.