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March 2012

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Subject:
From:
Kate Ambrus <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Forum Email List <[log in to unmask]>
Date:
Thu, 8 Mar 2012 18:36:06 -0800
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Hello - there is a difference between the mode of action aand therefore testing of a preservative and an antibiotic. The nature of the antibiotic is to prevent bacteria from multiplying, but it does not kill them. The antibiotic is expected to produce about a 3 log kill of bacteria and 1 log of yeast and mold. 
 
Therefore the presence of an antibiotic will not prevent ocurrence of bacateria that may contaminate the product. It will mereley control the levels, but not result in kill.
 
Kate Ambrus


________________________________
From: Madupa papaiah <[log in to unmask]>
To: [log in to unmask] 
Sent: Thursday, March 8, 2012 8:23 AM
Subject: Re: [PMFLIST] Antimicrobial efficacy

Jelena,
As usual I am surprised with the varied prospectives of microbiological
testing. The objective of addition of the preservative in a formulation is
to protect the formulation from any accidental contamination throughout the
product life cycle. Now in a situation where the formulation (API) is
antibacterial in nature, then the formulation is self preserving with
respect to the bacterial species but may still need to be protected from
yeast and moulds. So the formulation with active being an antibiotic,
should protect from representative microflora. The preservative efficacy
test should prove this point irrespective of whether the proservation
results from the active antibiotic or from the preservative. further, as a
matter of demonstration, you may perform the test on placebo with
preservative and placebo without preservative to prove the point either.
You may not even get the recovery in these type of formulations while
performing the test. By the way, is it required to demonstrate the recovery
when the formulation is known antibacterial by its active ingredient?
rgds,

On Thu, Mar 8, 2012 at 4:19 PM, Jelena Peric <[log in to unmask]>wrote:

> Dear All,
>
>
> have you ever tested the antimicrobial efficacy (i.e. efficacy of
> antimicrobial preservation) according to EP 5.1.3., or USP, on an
> antibiotic oral solution, or in any other antibiotic preparation that
> contains preservatives in addition to the antibiotic?
>
> The test is usually used to demonstrate that the chosen preservative
> concentration in a product is effective. During developmental stages of a
> product, different probes with different preservative concentrations are
> usually tested in order to demonstrate that the choice of a
> preservative and its concentration is justified, and that the product still
> complies even if the preservative content drops for what ever reason during
> shelf life.
>
> In my case, the situation is more complicated because of the presence of
> the antibiotic. What would be the right experimental design in my case?
> The simplest way would be to do the test on the final formulation, and to
> claim that the product is adequately preserved - but by doing so, I would
> not find out which test microorganisms are inhibited by the preservative,
> and which ones by the antibiotic, and what happens if the content of any of
> the antimicrobial substances drops during shelf life.
>
> Maybe I should test the final product formulation with the targeted
> preservative concentration, and than the same formulation but with the
> preservative concentration lowered (for example, 80% of the targeted
> concentration). Maybe I should see what happens if the content of the
> antibiotic drops to 80%, or what happens in the placebo (without the
> antibiotic) with the targeted preservative concentration or the lowered
> preservative concentration...
> What would you do in this case?
>
> Any thoughts will be appreciated,
>
>
> Jelena
>
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------------------
The PMFList (http://microbiol.org/PMFList_info.htm) is operated from
The Microbiology Network (http://microbiol.org) and supported by
our sponsors (http://microbiol.org/sponsor.htm) as a service to
the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.

Accugenix - http://www.accugenix.com

American Type Culture Collection - http://www.atcc.org

BD Diagnostic Systems - http://www.bd.com/ds/

Biolog - http://www.biolog.com

Biomerieux - http://industry.biomerieux-usa.com

Biotest - http://www.BiotestUSA.com/micro

Lonza Rapid Testing Solutions - http://www.lonza.com/rts

MicroBioLogics, Inc. - http://www.microbiologics.com

Pall - http://www.pall.com

NovaTek International - http://www.ntint.com

Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)

Steris - http://www.sterislifesciences.com/

Veltek Associates, Inc - http://www.sterile.com

=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

------------------
The PMFList (http://microbiol.org/PMFList_info.htm) is operated from
The Microbiology Network (http://microbiol.org) and supported by
our sponsors (http://microbiol.org/sponsor.htm) as a service to
the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.

Accugenix - http://www.accugenix.com

American Type Culture Collection - http://www.atcc.org

BD Diagnostic Systems - http://www.bd.com/ds/

Biolog - http://www.biolog.com

Biomerieux - http://industry.biomerieux-usa.com

Biotest - http://www.BiotestUSA.com/micro

Lonza Rapid Testing Solutions - http://www.lonza.com/rts

MicroBioLogics, Inc. - http://www.microbiologics.com

Pall - http://www.pall.com

NovaTek International - http://www.ntint.com

Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)

Steris - http://www.sterislifesciences.com/

Veltek Associates, Inc - http://www.sterile.com

=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

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