Dry Heat Sterilizer/ Tunnels Principle of Dry Heat Sterilizer/ Tunnels Construction of Dry Heat Sterilizer/ Tunnels Working of Dry Heat Sterilizer/ Tunnels Qualification Installation Qualification Operational Qualification Performance Qualification References

1. Department of Pharmaceutical Quality Assurance
Smt. B. N. B. Swaminarayan Pharmacy College, Salvav–vapi
Presented by:-
Machhi Dhruvi A.
2nd sem M.Pharm.

2.  Dry Heat Sterilizer/ Tunnels
 Principle of Dry Heat Sterilizer/ Tunnels
 Construction of Dry Heat Sterilizer/ Tunnels
 Working of Dry Heat Sterilizer/ Tunnels
 Qualification
 Installation Qualification
 Operational Qualification
 Performance Qualification
 References
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3.  Dry heat is the most commonly used method to sterilize & depyrogenate
pharmaceutical components, glassware & products.
 Commonly used dry heat sterilizers in pharmaceutical industry are;
1. Hot air oven
2. Tunnel sterilizer
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Dry Heat Sterilizer/ Tunnels

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Hot Air Oven Tunnel Sterilizer

5.  Sterilization is achieved by means of conduction.
 The heat in the chamber is absorbed by the item inside it & passes towards the
center of the item layer by layer.
 For the item to be fully sterilized, it needs to reach the required temperature.
 It inflicts damage by oxidizing molecules leading to the organism’s death.
Resistant spores are killed by exposing them at a higher temperature for a long
period of time.
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Principle of Dry Heat Sterilizer/ Tunnels

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Construction of Dry Heat Sterilizer/ Tunnels

7.  The DQ includes;
 Facility layout
 Decision of batch or continuous process
 Utility requirements & specifications
 Pressure differential requirements
 Required capacity of the sterilizer
 Type of materials to be sterilized
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Design Qualification

8.  All utility connections such as electrical & HVAC should meet the design
specifications .
 Materials of construction of both the sterilizer & the facility should meet the
design specifications
 The following pieces of equipment should be calibrated in situ:
 Temperature sensors & recording devices
 Temperature Controllers like in situ Pressure gauges, Belt speed controller &
recorder
 Velometers
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Installation Qualification

9. A. Temperature Monitors: The temperature controllers, recorders & sensors on
the process equipment must be calibrated before the unit can be operated
reliably.
B. Cycle Timer: The accuracy of the timer must be determined, so that assurance is
provided for cycle length.
C. Door Interlocks: If a unit is equipped with double doors, the interlocks must
operate such that the door leading to the aseptic area cannot be opened.
D. Heaters: All of the heating elements must be functional. It is preferable to have
them monitored continuously with ammeters in order that burned-out elements
can be immediately detected.
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Operational Qualification

10. E. Cooling Coils: To enable a faster cool-down cycle, the air is often circulated
across coolant coils.
F. Belts: The belt speed is a critical operating parameter in continuous hot-air
tunnels. Recorders for charting the belt speed are recommended for units with
adjustable speed settings
G. Particulate Counts: Particulate counts should be checked before & after
sterilization.
H. Chamber Leaks: The perimeter of the doors for batch sterilizers should be
checked for air leakage while operating.
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11. (1) Air balance determination: In an empty oven, data are obtained on the flow
rates of both intake & exhaust air. Air should be balanced so that positive pressure is
exerted to the nonsterile side when the door is opened.
(2) Heat distribution of an empty chamber: Thermocouples should be situated
according to a specific predetermined pattern.
(3) Heat-penetration studies: These studies should be designed to determine the
location of the slowest heating point within a commodity at various locations of a
test load in the sterilizer. Thermocouples are placed in the commodities located in
the areas likely to present the greatest resistance to reaching the desired temperature.
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Performance Qualification of Hot Air Oven

12. (4) Mechanical repeatability: During all these studies, mechanical repeatability in
terms of air velocity, temperature consistency, reliability & sensitivity of the oven &
instrumental controls must be verified.
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13. (1) Air Balance Determination:
 In this study, items being sterilized are moving exposed to different air systems
(e.g., heating zone & cooling zone).
 Air flow must be balanced in order to provide a gradual decrease in air
temperature as items move along the conveyor.
(2) Heat-Distribution Studies:
 Thermocouples used in tunnel sterilizer validation must be sufficiently durable to
withstand the extremely high temperatures (23000 C) in the heating zone area of
the tunnel.
 Heat-distribution studies should determine where the cold spots are located as a
function of the width of the belt & height of the tunnel chamber.
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Performance Qualification of Tunnel Sterilizer

14. (3) Heat-Penetration Studies:
 Prior to microbial challenge testing of the tunnel sterilization, heat-penetration
studies must be completed in order to identify the cool spot in the entire load.
 3 to 5 replicate runs for each commodity size & every loading configuration
should be done using 10 to 20 thermocouples distributed throughout the load.
 Careful analysis of the temperature data after each run will be valuable in the
determination of the cool spot.
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15. (4) Mechanical Repeatability:
 Tunnel sterilizers must demonstrate mechanical repeatability in the same manner
as batch ovens.
 Air velocity, air particulates, temperature consistency & reliability of all the
tunnel controls (heat zone temperatures, belt speed) must be proved during the
physical validation studies.
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16. REFERENCES
1. http://www.slideshare.net/JadhavAnkushJadhav/qualification-of-
manufacturing-equipments?from_m_app=android
2. Subrahmanyam CVS, Setty JT, Sarasija S & Devi VK in “ Pharmaceutical
Engineering- Principles & Practices”, Vallabh Prakashan, New Delhi, 2001,
390-391, 397-399.
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17. Thank
You
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