August 25, 2021: Pharmaceutical Interview Questions and Answers

#Sterilization #LocationOfBiologicalIndicator #EmptyChamberMapping #CalibrationAndImpactOnSterilization

1. Why air should be removed from the autoclave chamber while sterilization?

The insulating properties of air interfere with the ability of steam to transfer its energy to the load, achieving lower lethality than associated with saturated steam.

2. Where must to have location for the biological indicator during sterilization validation?

Potentially difficult to reach locations within the sterilizer load or equipment train (for SIP applications) should be evaluated. For example, filter installations in piping can cause a substantial pressure differential across the filter, resulting in a significant temperature drop on the downstream side. We recommend placing biological indicators at appropriate downstream locations of the filter.

3. Why empty chamber mapping studies required during the sterilizer validation?

Empty chamber studies evaluate numerous locations throughout a sterilizing unit (e.g., steam autoclave, dry heat oven) or equipment train (e.g., large tanks, immobile piping) to confirm uniformity of conditions (e.g., temperature, pressure).

4. How heat penetration study shall be done while sterilizer validation?

Heat penetration studies should be performed using the established sterilizer loads. Validation of the sterilization process with a loaded chamber demonstrates the effects of loading on thermal input to the items being sterilized and may identify difficult to heat or penetrate items where there could be insufficient lethality to attain sterility. The placement of biological indicators at numerous positions in the load, including the most difficult to sterilize places, is a direct means of confirming the efficacy of any sterilization procedure. In general, the biological indicator should be placed adjacent to the temperature sensor so as to assess the correlation between microbial lethality and predicted lethality based on thermal input.

5. What types of calibration should be checked which could have impact on sterilization?

i. Temperature and pressure monitoring devices for heat sterilization should be calibrated at suitable intervals. The sensing devices used for validation studies should be calibrated before and after validation runs.

ii. Devices used to monitor dwell time in the sterilizer should be periodically calibrated.

iii. Instruments used to determine the purity of steam (as applicable) should be calibrated. iv. For dry heat depyrogenation tunnels, devices (e.g. sensors and transmitters) used to measure belt speed should be routinely calibrated.

Reference: FDA Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing – Current Good Manufacturing Practice – September 2004

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