Privatsphäre-Einstellungen

Haltbarkeit von biologischen Indikatoren für die Dampfsterilisation

Michael Pfeiffer Boehringer Ingelheim Pharma KG, Ingelheim/Rhein

Shelf Life of Bioindicators for Steam Sterilisation

The third edition of the European Pharmacopoeia (Ph.Eur.; effective from January, 1 st , 1997) states that biological indicators are to be stored at specified temperature and that an expiry date has to be set. In addition to that, biological indicators shall have a specified spore population with a certain resistance (D-value ¹⁾ ) against the sterilising agent. For steam sterilisation, spores of Bacillus stearothermophilus (e.g. ATTC 7953) are recommended. The number of viable spores/indicator shall exceed 5 ×10⁵ and the D-value of these spores at T = 121 °C shall exceed 1.5 min. The use of biological indicators for routine monitoring of sterilisation is mainly justified for sterilisation with gases, but in case of steam sterilisation it is also recommended in certain cases. To test deteriorating effects of prolonged storage times on spores of biological indicators, indicators for monitoring irradiation sterilisation are suited best as only one parameter (adsorbed dose (kGy) which can easily be determined by using dosemeters) has to be monitored. But also indicators for steam sterilisation with two relevant parameters (time and temperature, which can easily be monitored by physical/technical means) can be used to investigate storage conditions. In the present investigation it could be demonstrated that storage of biological indicators up to 2 years longer than the stated expiry date does neither affect the viability of the indicator spores nor their resistance against the sterilising agent: In cases like that it could be helpful if the European Pharmacopoeia like the US Pharmacopoeia could describe ranges in which the certified parameters are to be determined.

1) D-value: The time (in minutes) required to reduce the specified spore population to 1/10 (by 90 %) at a given temperature (e.g. 121 °C).

Key words Bioindikatoren, Haltbarkeit, Verfalldatum · Dampfsterilisation