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  1. #1
    Sreekanth Kosaraju
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    Post Heat Penetration test - Steam sterilizer

    Dear all,

    Please guide me in the following-

    1) What is the frequency of Heat penetration study by Bowie dick test method? What is the rationale behind it & regulatory specifications? Ours is steam sterilizer.
    2) On what basis we are deciding the number of temperature sensors while validating steam sterilizer & Tunnel (Dry heat sterilizer)? Is there any guidance for the same?
    3) In tunnel we are going for both sterilization & Depyrogenation. But in Autoclave we are doing only sterilization.Can we remove endotoxins in steam sterilization? If not what will be the fate of the items sterilized? How can it be explained? What is the minimum temperature required to remove endotoxins?

    With Regards
    Sreekanth Kosaraju

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  3. #2
    Validation Guru
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    Default

    Dear Sreekanth

    1) What is the frequency of Heat penetration study by Bowie dick test method? What is the rationale behind it & regulatory specifications? Ours is steam sterilizer.
    Answer!
    Bowie-Dick test be performed every day that the prevacuum steam sterilizer is in operation. In addition, three consecutive Bowie-Dick tests
    must show a “pass” before a steam sterilizer is put back into use after installation or major repair.


    2) On what basis we are deciding the number of temperature sensors while validating steam sterilizer & Tunnel (Dry heat sterilizer)? Is there any guidance for the same?

    Answer
    As per the size of autoclave it is decided to map and locate the temperature probes. A guide line can give u the outline generally its upto u to select the suitable study design.


    3) In tunnel we are going for both sterilization & Depyrogenation. But in Autoclave we are doing only sterilization.Can we remove endotoxins in steam sterilization? If not what will be the fate of the items sterilized? How can it be explained? What is the minimum temperature required to remove endotoxins?
    Answer!
    Endotoxins can`t be removed by autoclaving, but it is to be removed preliminary, certain measures and precautions are taken before manufacturing like WFI testing, Ampoule or Vial depyrogenation, then after filling and autoclaving product is subjected on LAL test for the confirmation.


    Regards,
    Shahid Ali
    QA Manager
    Addis Pharmaceutical Factory SC, Ethiopia
    Last edited by Shahid Ali; 09-08-2007 at 03:57 PM.

  4. #3
    nadeem javed
    Guest

    Default Endotoxin control

    Dear Sreekanth,

    You can control the Pyroburden (endotoxin amount) by installing charge filter of any brands (e.g Durapore charge filter from millipore)) on WFI lines. These filters carries positive charge and due to negative charge carried by endotoxin it electrostatically retain on the filter.

    Regards,
    Nadeem Javed

  5. #4
    Sreekanth Kosaraju
    Guest

    Smile

    Dear
    Mr.Shahid Ali & Mr. Nadeem Javed,

    Sorry, I was late in viewing your valid answers. Thankyou for your reply.

    With regards
    Sreekanth Kosaraju

  6. #5
    Ahsan Khan
    Guest

    Default

    Dear Mr Shahid ALi

    you replied to Sreekanth as follows

    ) On what basis we are deciding the number of temperature sensors while validating steam sterilizer & Tunnel (Dry heat sterilizer)? Is there any guidance for the same?

    Answer
    As per the size of autoclave it is decided to map and locate the temperature probes. A guide line can give u the outline generally its upto u to select the suitable study design.



    But how can we decide like that ? there must be a recommended distance between the temperature probe.

    Can any one suggests in this regards

  7. #6
    Validation Guru
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    Default

    Quote Originally Posted by Ahsan Khan View Post
    Dear Mr Shahid ALi

    you replied to Sreekanth as follows

    ) On what basis we are deciding the number of temperature sensors while validating steam sterilizer & Tunnel (Dry heat sterilizer)? Is there any guidance for the same?

    Answer
    As per the size of autoclave it is decided to map and locate the temperature probes. A guide line can give u the outline generally its upto u to select the suitable study design.



    But how can we decide like that ? there must be a recommended distance between the temperature probe.

    Can any one suggests in this regards
    I m agreed with Ahsan comments, I am ellaborating the heat mapping conept,
    To establish the temperature profile throughout the empty chamber. The temperature distribution in this test is influenced by the type, size, and design of the sterilizer. Empty chamber studies are commonly conducted in triplicate to demonstrate the stability of the system. Locations to be monitored for temperature include the chamber drain, temperature sensor (if located in a location other than the drain) in the corners of the sterilizer, and in the water spray line (just before the spray nozzle, if present). The number of temperature sensors utilized in the heat distribution study can vary with sterilizer size. As the distribution of the steam is being studied,temperature probes should not be in contact with the internal surfaces of the sterilizer.


    Thanks
    Shahnawaz Sajid (Ph.D)

  8. #7
    Validation Guru
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    Quote Originally Posted by Shahnawaz View Post
    I m agreed with Ahsan comments, I am ellaborating the heat mapping conept,
    To establish the temperature profile throughout the empty chamber. The temperature distribution in this test is influenced by the type, size, and design of the sterilizer. Empty chamber studies are commonly conducted in triplicate to demonstrate the stability of the system. Locations to be monitored for temperature include the chamber drain, temperature sensor (if located in a location other than the drain) in the corners of the sterilizer, and in the water spray line (just before the spray nozzle, if present). The number of temperature sensors utilized in the heat distribution study can vary with sterilizer size. As the distribution of the steam is being studied,temperature probes should not be in contact with the internal surfaces of the sterilizer.


    Thanks
    Dear Shahnawaz
    Locations for probes are defined in guidelines but typically Mr Ahson is asking for the Recommended distance. In fact Recommended distances among the probes is not given in any guideline. Mapping is to be done suitably keeping in mind the type, size, and design of the sterilizer.
    Dr. Shahid A Syed
    QA/Validation Specialist
    Penn Pharmaceutical
    www.pennpharm.com

  9. #8
    Validation Guru
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    Default

    Quote Originally Posted by Shahid Ali View Post
    Dear Shahnawaz
    Locations for probes are defined in guidelines but typically Mr Ahson is asking for the Recommended distance. In fact Recommended distances among the probes is not given in any guideline. Mapping is to be done suitably keeping in mind the type, size, and design of the sterilizer.
    Dear Shahid,

    I have already desribed in earlier post that the most suitable places where the thermocouples can be placed during autoclave qualification it not just depend on type, size, and design of the sterilizer,, there are some other places which i identified in my earlier post should be covered. YOU ARE RIGHT, Recommended distances among the probes is not given in any guideline.
    Shahnawaz Sajid (Ph.D)

  10. #9
    ster.yogesh
    Guest

    Default No. of probes

    Quote Originally Posted by Shahnawaz View Post
    Dear Shahid,

    I have already desribed in earlier post that the most suitable places where the thermocouples can be placed during autoclave qualification it not just depend on type, size, and design of the sterilizer,, there are some other places which i identified in my earlier post should be covered. YOU ARE RIGHT, Recommended distances among the probes is not given in any guideline.
    Dear Sir,
    I want to konw how we decide how many no. of probes to be placed in chamber of autocalve,is this depends on size of chamber, then what;s the actual calculating farmula for that?
    regards,
    yogesh

  11. #10
    Validation Guru
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    Default

    Quote Originally Posted by ster.yogesh View Post
    Dear Sir,
    I want to konw how we decide how many no. of probes to be placed in chamber of autocalve,is this depends on size of chamber, then what;s the actual calculating farmula for that?
    regards,
    yogesh
    Dear Yogesh,

    I have answered it earlier, I am ellaborating the heat mapping conept,
    To establish the temperature profile throughout the empty chamber. The temperature distribution in this test is influenced by the type, size, and design of the sterilizer. Empty chamber studies are commonly conducted in triplicate to demonstrate the stability of the system. Locations to be monitored for temperature include the chamber drain, temperature sensor (if located in a location other than the drain) in the corners of the sterilizer, and in the water spray line (just before the spray nozzle, if present). The number of temperature sensors utilized in the heat distribution study can vary with sterilizer size. As the distribution of the steam is being studied,temperature probes should not be in contact with the internal surfaces of the sterilizer.

    I think this may help you out.
    Shahnawaz Sajid (Ph.D)

  12. #11
    Validation Guru
    Join Date
    Dec 2006
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    Default

    Typically, I have seen about 18 TCs used to map a chamber. This had to do with two issues

    1.Kaye validators had 18 or 16(i think it was 16 but 18 works better for my example) input modules. Now I think the Validator 2000 take 36 TC per module.

    2. The flange that the TC's had to enter wasn't large enough to allow more than 16 TCs into the chamber.

    So taking into account the limited number of TCs and that at least one in the drain, one at the control point, You have 14 to work with. Typically, you want to geometrically distribute the TCs in the chamber(top, middle, bottom, side to side, and front to back.) I like to cross section the front middle and back...like this looking in the front. Then double up the drain, just in case one fails.
    |__0_________0__|
    |_______________|
    |_______0_______|
    |_______________|
    |__0_________0__|
    Last edited by meyert; 01-11-2008 at 09:05 PM.

  13. #12
    Validation Guru
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    Quote Originally Posted by meyert View Post
    Typically, I have seen about 18 TCs used to map a chamber. This had to do with two issues

    1.Kaye validators had 18 or 16(i think it was 16 but 18 works better for my example) input modules. Now I think the Validator 2000 take 36 TC per module.

    2. The flange that the TC's had to enter wasn't large enough to allow more than 16 TCs into the chamber.

    So taking into account the limited number of TCs and that at least one in the drain, one at the control point, You have 14 to work with. Typically, you want to geometrically distribute the TCs in the chamber(top, middle, bottom, side to side, and front to back.) I like to cross section the front middle and back...like this looking in the front. Then double up the drain, just in case one fails.
    |__0_________0__|
    |_______________|
    |_______0_______|
    |_______________|
    |__0_________0__|
    Meyert is right
    Shahnawaz Sajid (Ph.D)

  14. #13
    Validation Expert
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    Apr 2008
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    Yes, Kaye Validator 2000 has 36 termocouples. 3 moduls with 12 termocouples each.
    I agree with Mr. Meyert, too... we use that configuration of themrocouples, too. And one tc in the drain.
    Zeljko Joksimovic

    Independent Expert Associate for Equipment Qualification

  15. #14
    Validation Analyst
    Join Date
    May 2008
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    Default

    This is guidence from PDA. I think this can solve all your worries about no. of probes for validation

    Temperature monitors are placed so that the areas of the sterilizer expected to bewarmest and coolest are monitored. Typically a minimum of 10 functional probes are used for maximum loads but any number may be used to assure full coverage of the chamber and/or load. Use of a formula such as one temperature probe per cubic foot of chamber volume is a good method for assuring consistency of mapping across different sterilizers. Following are methods in common use for performing temperature mapping in different types of moist heat sterilizers

  16. #15
    Validation Analyst
    Join Date
    Jun 2008
    Posts
    3

    Default B&D test

    Hello,
    I have aquestion concerning the B&D test.
    According to the standards the test should be performed for 3.5 minutes in 132 or 134 degrees depends on the standard you are using.

    our autoclave has 4 probes controlling the process.
    does 132 degrees is the minimum temperature?
    can i controll the process in a way that the temperature should be programmed for 132 - 134 with a set point of 132.3.

    does the required temperature is minimum / maximum?

    There is no way to control this test strictly in 132 degree.

    Can anyone clarify how this test should be done and what are the limitations?

    Thanks in advance
    Yossi

  17. #16
    Validation Analyst
    Join Date
    May 2008
    Posts
    8

    Thumbs up Bowie Dick Test

    I believe that a UK company called Albert Browne makes Bowie Dick test packs under the Steraffirm brand. In addition to a 121-124C cycle, they have packs for 132C and 134-137C. The patterns that result from a failure seem to indicate the way in which the cycle failed and can be a very good diagnostic tool.

    Perhaps someone from Albert Browne might be able to help if you Google them?

    Hope this helps
    Cleanerman

  18. #17
    Validation Analyst
    Join Date
    Nov 2009
    Posts
    1

    Default Dear all

    The DART(R) Daily Air Removal Tests and STERAFFIRM (TM) Bowie - Dick Test Packs are single use test packs to assess the effectiveness of air removal from pre - vacuum steam auto claves. The STERAFFIRM (TM) Bowie - Dick Test Packs are for use with 121 - 124 degree celcius. pre - vacuum sterilizers.
    The DART(R) test packs are designed to be functionally equivalent to the Bowie - Dick Test described by the AAMI and are for use with 132 to 134 degree celcius pre vacuum sterilizers

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