DEFINIITION

Shelf life is the term or period during which a commodity remains suitable for the intended use. ”Shelf life” refers to the durability under specified storage and transport conditions defined by the manufacturer until the immediate packaging is opened for the first time.

An expiry date (“use-by” date) is the termination of shelf life, after which a percentage of the commodity, e.g., medical devices, may no longer function as intended.

To determine if a particular device requires an expiry date, there are a number of different parameters that must be considered. The device must be analyzed to determine if

• it is susceptible to degradation that would lead to functional failure
• the level of risk that the failure would resent

For some devices, e.g., tongue depressors, it is not reasonable to assign a shelf life because of the small likelihood of time-dependent product degradation and the lack of serious consequences if it did fail to perform as designed. For devices intended to treat life-threatening conditions, the failure rate should approach zero within the labeled shelf life.

SHELF LIFE TESTING OF DEVICES AND PACKAGING

For CE marking of Medical Devices, as a part of the Technical File, manufacturers need to define the shelf life of their device, which is also mandatory as a component of Risk assessment. Shelf life refers to the durability under specified storage and transport conditions defined by the manufacturer until the immediate packaging is opened for the first time.

Essential requirements are set forth in the MDR and in the ISO 13485

Based on the type of the device, chemical, physical, microbiological, toxicological, technological as well as packaging aspects have to be considered while determining the shelf life of a product. This also applies to the storage and climatic conditions: compliance to the climate zones of the target markets have to be taken into consideration also. In case of Active medical devices the lifetime of the device is calculated by a compiled calculation of all the critical components of the device.

Testing should be conducted on a minimum of three to four batches to eliminate the variability related to the raw material and production processes. Also the intervals between tests conducted need to be risk based and has to be distributed throughout the shelf life of the product.

• Product testing: ease of assembly, simulated use and ease of use, dose accuracy, tamper evidence, visual inspections, dimensions, connection compatibility
• Packaging testing: ISO 11607 package validation, integrity, seal strength, sterile barrier system, transport simulation

The shelf life can be determined by either a real time or an accelerated ageing test where Arrhenius Law is applied in a simulated environment.

EXPIRY OF MD WITH LIMITED SHELF LIFE

Sterile medical devices (ex: injection supplies)

A sterile item with a passed expiry date cannot be considered as sterile anymore and must be eliminated. If the expiry date only mentions the month and the year, it is the end of the month which has to be considered the use-by date. The evolution with time of the constituent materials of medical/surgical equipment can only be determined by the manufacturer who knows exactly its composition.

The period of validity only applies if transport and storage are carried out under good conditions (protected from heat, humidity and light) and for items of which the sterile primary packaging is intact. The item cannot be considered sterile any more if the primary packaging is deteriorated (cracks, moldy).

Non sterile medical devices (ex: adhesive tape)

An item with a passed expiry date does no longer have the properties required for its use and should not be used. The period of validity only applies if transport and storage are carried out under good conditions (protected from heat, humidity and light) and for items of which the primary packaging is intact.