Minimum load in Autoclave validation

Hi All,

I have questions about the minimum load in autoclave validation:

  1. Why do minimum load? It tell us about what?
  2. How to define minimum load, the less load the closer to mini load? one 10mL glass vial can be accepted as a minimum load?
  3. for porous and nonporous load, each should has its own mini load?

could any one with the experience clarify this with me?

Thanks in advance.

  1. Minimum load must be qualified because for porous load it is worst case for air removal phase.

For liquid load minimum load can be worst case because sterilization phase can start faster rather than for maximum load (control probes are heating faster) and load can have delay to reach sterilization temperature.

For some liquid loads control probe are in containers and they faster reach sterilization temperature compared to maximum load. In that case product later reach sterilization temperature compared with maximum load.

When we talk about liquid loads, you should develope cycle for maximum and for minimum load!

  1. Minimum load is minimum that you really sterilized in autoclave. If your load is 10ml vials, minimum that you really put inside is minimum load ( I think that you dont sterilize one vial).

  2. What is minimum load you should explain in your rationale. You should list all loads and compare them and see what you really can put in the autoclave as minimum load. What is worst item for sterilization for maximum load is worst item for minimum load.For porous load, one filter capsule can be minimum load (for example) rather than basket for stoppers.

thanks so much for explanation!

If I understand correctly, in minimum load, the sterilization cycle start earlier compared to maximum load while the air may not completely removed, so the real sterilization effect need to be validated.



for liquid loads in some occassions min load can be worst case compare to maximum load. In this situation , heating of control probes for maximum load needs more time and whole load will be heated longer than compared with minimum load where control probes are heating faster and sterilization cycle start faster. It depends of the position of control probes, of the load configuration and of rate of heating and cycle design.

For porous load, you need to remove greater volume of air from the chamber compared to maximum load. Trapped air can affect sterilization.

So, for both cases, liquid and porous load, min and max load must be validated:

21CFR 211.113 Control of microbiological contamination.

(b) Appropriate written procedures, designed to prevent microbiological contamination of drug products purporting to be sterile, shall be established and followed. Such procedures shall include validation of all aseptic and sterilization processes.

it is very helpful!

Many thanks!

Dear Sir,

Can you guide me what is frequency to record the temperature on Prints during mapping? I mean we used to set one minute to record the temperature on prints. Is it ok or needs to reduce it?

Thanks in advance

Pulla Reddy Karnati.

One minute is not ok cause it is a to long period.
First, for example how can you calculate your equilibration time (which must be under 15/30 seconds) if you take take samples every 1 minut?
Second, for standard cycle 121oC / 15 minutes you will have only 15 samples so there are big chances not to record temperature drops bellow 121oC. If you use Kaye Validator you can set to record samples every 1,2 or 3 second depends of number of SIMs (12 inputs per second). From my experience, 3 seconds for a cycles less than 3,4 hours are ok, you can clearly follow your process and you can not collect too many samples.