An Introduction To Residual Seal Force (RSF) Of Product Requiring Deep Cold Storage

By: Roger Asselta, VP of Technical Affairs

Since the early part of the last century crimped, stoppered vials have been a primary packaging system for parenteral medicines. The system has proved effective and reliable in containing and protecting the quality, safety and efficacy of many injectable drug products. Still widely used today the storage requirements of some vaccines, biopharmaceuticals and gene and cell therapies such as deep cold storage present new challenges to the robustness of the traditional vial systems. Traditionally, drug products may have be stored and transported at or near room temperature (20°), chilled (4 to 8°) or frozen (down to -20°). Today, some vaccines and biopharmaceuticals require temperatures down to -80° and some cell therapies need cryopreservation (-150 to -195°).

For a vial system to be suitable for its intended use of containing and protecting the quality, safety and efficacy of the parenteral drug product it must be “well sealed” and maintain integrity through administration to the patient. This life-cycle approach mandates a thorough understanding of Container-Closure Integrity (CCI), Maximum Allowable Leakage Limits (MALL), and Inherent Package Integrity (IPI).

An important seal quality test to assess how well a vial is sealed is the measurement of the Residual Seal Force (RSF) of the compressed rubber stopper (USP<1207.3). Correlating RSF to a Container Closure Integrity Test (CCIT) method and evaluating changes over time and conditions will determine the system’s Inherent Package Integrity.