Depyrogenation Ovens Qualification

Dry heat sterilization (or Depyrogenation) is a process aimed at the reduction in the level of pyrogens with the use of hot air in temperature ranging from 160° C up to 400° C. The temperature used depends on the duration of the process. Gravity or mechanical heat convection can be used for this process. The former uses the natural interaction between air and different temperatures and the latter produces a specific flow of air with the help of a blower.

Depyrogenation is mainly used in the sterilization of vials for aseptic filling. The process is also useful to sterilize assembled and packaged materials, since heat conduction does not require the contact of the product with steam or water.

However, not all products can withstand the high temperatures required for this kind of process (e.g. metal goods, heat sensitive solutions, etc.).Batch and dynamic are the two main techniques for depyrogenation. Batch production is usually done in static ovens where the product is placed in metal crates and exposed to high temperatures. Dynamic involves the use of a depyrogenation tunnel, where goods are transported over a continuous band through different heating zones of the tunnel.