Sterilization Process

TYPICAL STERILIZATION PROCESS IN AUTOCLAVE FOR POLYPROPYLENE BAGS AND/OR POLYPROPYLENE BOTTLES

Sterilization: definition and methods

With the “sterilization” term we refer to any process, chemically or physically, that eliminates (removes) or kills all form of pathogen life, including transmissible agents (such us fungi, bacteria, viruses, spore forms, etc.) present on a surface, contained in a fluid, in medication, or in a compound such as biological, irradiation, high pressure and particular filtration.

There are many kind of sterilization process for different application and sector:

By heating:
By chemical process: Below, we would like write a few description of this process, a small reference on this application.
 

ISBM technology and sterilization process

The ISBM technology (Injection – Stretch – Blow – Moulding) is a double step process, completely different from the BFS (Blow – Fill – Seal) process.
This process allows the operator to keep under control all the fundamental parameter and adjusts them in case it is required. The recovery time is also less than the BFS.
With the ISBM technology the sterilization process is 100% allowed. The PP bottles and the PP bags made with the double step technology are completely sterilisable after the filling and closing process, according the FDA statement and GMP process.
In this field (sterilization process) G.F. experiences “suggest” (please note suggest) to use as sterilization method based on a Super-heated water sterilizers.
This kind of sterilization is designed to preform terminal sterilization of large volume infusion and parenteral solutions in PP containers (bags and bottles).
The sterilization process is made by an autoclave and it is based on a differential pressure under heat exposure under heat exposure, a counter pressure inside the chamber during the entire cycle in order to minimize the differential pressure across the container and avoid excessive deformation.
 
Are present several curves:  
In the sterilization cycle, the F0 process (i.e. temperature and time) is fixed according the FDA process.

Additionally: Before to obtain the optimized sterilization process and curve and the correct bottles shape, it is necessary to perform several tests with the bottles, by adjusting chamber pressure, chamber temperature, pre heating and cooling time.
 
Furthermore, it is important consider the following items:
  1. The PP bottle linear dimensional change before and after autoclave, this is unavoidable, due to following principles:
 
2.      The level of the geometric shape change also unavoidable, as it is a combined result of linear dimensional change mentioned above. The key to keep bottles in their proportional shape is to maintain the dynamic pressure balance between inside and outside of the bottles during the whole process of autoclave, no matter higher of lower rate of bottle linear dimensional changes
 
3.      Preheating stage(e.g. temperature raised to 121°C). During this process, the pressure are increased both inside and outside of bottles but the pressure increasing speed between inside and outside of bottles must to be the same; pressure increasing speed of outside bottles is faster than that of inside bottles therefore, autoclave tank pressure should be discharged in order to keep dynamic pressure balance
 
4.      Sterilization stage(e.g. temperature maintained at 121°C min). The temperature in this stage must be kept constant (eg.g 121°C), with no change both curves of the temperature and pressure must stay as much as possible in horizontally flat
 
5.      Cooling stage(e.g. temperature dropped from 121°C in 40 min) special attention must be paid at this stage especially temperature 121 drop to around 85°C. during this process, the pressure are decreased both inside and outside of bottles but the pressure decreasing speed between inside and outside of bottles are not the same pressure decreasing speed of outside bottles is farest than that of inside bottles therefore, autoclave tank pressure should be compensated in order to keep dynamic pressure balance.
 
Please note that the above information must not be considered as a must. The sterilization conditions that best fit particular bottles are based on actual tests, since each product and equipment have their own factors to be adjusted case by case.