Store Samples with Adequate Overage for Retesting and Stability Studies

Retain Adequate Overage When Storing Samples for GMP Compliance

Remember: Samples must be stored with sufficient quantity for all potential retesting, investigations, and regulatory queries throughout their shelf life.

Why This Matters in GMP

Retention samples serve as reference material for retesting, complaint investigation, or stability studies. Insufficient quantity can prevent confirmation of original results or hinder root cause analysis in case of market complaints. GMP regulations require that samples be representative of the batch, stored under controlled conditions, and retained for the full product shelf life or longer. Adequate overage ensures analytical repeatability and supports regulatory inspections. It also enables continued product surveillance and lifecycle management. Failure to store enough sample material may lead to non-compliance, inability to defend against claims, or batch rejection.

Also Read: Best Practices for Achieving PMDA GMP Compliance in Drug Development

Regulatory and Compliance Implications

FDA 21 CFR Part 211.170 specifies that reserve samples be stored in sufficient quantity to perform complete analysis. EU GMP Chapter 6 and WHO GMP mandate retention of reference samples under defined conditions. Schedule M emphasizes that samples be retained in adequate quantity and labeled for traceability. Auditors verify sample logs, storage conditions, and retesting capabilities. Inadequate sample quantities or missing batches may result in 483 observations, especially during post-marketing surveillance or complaint investigations.

Implementation Best Practices

Define overage quantity (e.g., 2× test volume) for each product based on test scope and reanalysis needs.
Store samples in controlled temperature and humidity environments per product label.
Label retention samples with product name, batch number, manufacturing date, and expiry.
Maintain sample issuance logs to track retesting events and usage.
Review storage inventories periodically and reconcile against batch release records.

Also Read: How to Track the Effectiveness of Continuous Improvement Initiatives in GMP

Regulatory References

FDA 21 CFR Part 211.170 – Reserve Samples
EU GMP Chapter 6 – Quality Control
WHO GMP – Sample Retention Guidelines
Schedule M – Sample Storage and Overage Policy