Sterilization validation

Sterilization validation according to ISO 11137-2

Micro-Serve laboratory provides a coordination service of the initial bioburden and sterilization validation along with a full validation report.
The main advantage of this very thorough and cost-effective approach is that it covers all areas of the ISO 11137-2 requirements.

Micro-Serve laboratory has many experience providing validations for unique or complex medical devices, or medical devices that cannot handle large doses of radiation.
A radiation validation determines the appropiate radiation sterilization dose for a medical device that requires a sterile label claim.

Usually the sterilization dose must represent a sterility assurance level (SAL) of 10-6, which means a one in a million probability of a non-sterile product.
The validation incorporates a bioburden recovery efficiency test, bioburden testing, a sub-lethal radiation dose (verification dose) and sterility testing.

Sterilization validation methods

The most common validation methods are VDmax (verification dose maximum) and Method 1. Both methods are available in a single batch validation or a full 3-batch validation.

“Using Bioburden Information” Information must be obtained regarding the number of the micro-organisms on or in a product. This is then compared to a standard distribution of resistances (SDR) to determine the minimum sterilization dose. The Bioburden level will lead to a certain irradiation dose.

 “Substantiation of 25 or 15 kGy” This method describes the selection of the minimum sterilization dose of 25 kGy. Laboratory testing is used to demonstrate that a SAL 10-6 has been achieved with the selected minimum sterilization dose. The limit on allowable numbers of bioburden is 1,000 cfu per product unit for the VDmax25 and 1.5 cfu per product for the Vdmax15.

“Fraction positive information from incremental dosing” With this, less frequently used method, information is obtained about the resistance to radiation of micro-organisms as they occur on the product. This specific resistance is being used for dose setting.

“Substantiation of a selected sterilization dose” This method allows the selection of additional doses next to 25 or 15 kGy. With this VDmax method doses of 17.5, 20, 22.5, 27.5, 30, 32.5, and 35 kGy can be substantiated.


Frequently asked questions

20 non sterile samples, of which we use 10 for bioburden analysis and 10 for the verification experiment.