Abstract
When calculating of the physical F121.1°C-value by the equation
F121.1°C = t · 10T°121.1/z
the temperature (T), in combination with the z-value, influences the F121.1°C-value exponentially.
Because the z-value for spores of Geobacillus stearothermophilus often varies between 6 and 9, the biological F-value (FBIO) will not always correspond to the F0-value based on temperature records from the sterilization process calculated with a z-value of 10, even if the calibration of both of them are correct. Consequently an error in calibration of thermocouples and difference in z-values influences the F121.1°C-values logarithmically.
The paper describes how results from measurements with different z-values can be compared. The first part describes the mathematics of a calculation program, which makes it easily possible to compare F0-values based on temperature records with the FBIO-value based on analysis of bioindicators such as glycerin-water-suspension sensors. For biological measurements, a suitable bioindicator with a high D121-value can be used (such a bioindicator can be manufactured as described in the article “A Method of Increasing Test Range and Accuracy of Bioindicators—Geobacillus stearothermophilus Spores”).
By the mathematics and calculations described in this macro program it is possible to calculate for every position the theoretical temperature difference (ΔTth) needed to explain the difference in results between the thermocouple and the biointegrator. Since the temperature difference is a linear function and constant all over the process this value is an indication of the magnitude of an error. A graph and table from these calculations gives a picture of the run.
The second part deals with product characteristics, the sterilization processes, loading patterns. Appropriate safety margins have to be chosen in the development phase.
- Bioindicator
- Biointegrator
- Geobacillus stearothermophilus
- Steam sterilization
- F0- value
- FBIO-value
- F121.1°C-value
- z-value
- D121-value
- Sterilization
Footnotes
- Copyright © Parenteral Drug Association. All rights reserved.
PDA members receive access to all articles published in the current year and previous volume year. Institutional subscribers received access to all content. Log in below to receive access to this article if you are either of these.
If you are neither or you are a PDA member trying to access an article outside of your membership license, then you must purchase access to this article (below). If you do not have a username or password for JPST, you will be required to create an account prior to purchasing.
Full issue PDFs are for PDA members only.
Note to pda.org users
The PDA and PDA bookstore websites (www.pda.org and www.pda.org/bookstore) are separate websites from the PDA JPST website. When you first join PDA, your initial UserID and Password are sent to HighWirePress to create your PDA JPST account. Subsequent UserrID and Password changes required at the PDA websites will not pass on to PDA JPST and vice versa. If you forget your PDA JPST UserID and/or Password, you can request help to retrieve UserID and reset Password below.
