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D-Value changes in solution components and pH

Davin C. Enigl enigl at aol.com
Mon Jul 1 11:22:26 EST 2002

On 28 Jun 2002 14:15:55 -0700, strangerhere at juno.com (Rob) wrote:

>I'm looking for a study that I can reference with respect to the
>changes in d-value of an indicator organism in water compared to
>different substances in water.
>For instance, given the same bacteria (B.stearothermophilus)how does
>the d-value comapre when sterilized in water as a carrier to a saline
>solution, or sucrose, or a cyclodextrin?  Does a lower pH, say 5.5
>effect the d-value of a suspension?  I know that concentrations of
>these compounds in solution will have an effect, but I am looking for
>ball park numbers, or even a general direction of the d-value.  I
>would be interested in hearing of unofficial tables, but would really
>like to see something I could reference.
>For those not in the industry, as part of developing a drug for
>clinical trials and for distribution, the FDA requires that we assure
>that the drug product is safe.  One aspect of this is that, with
>pararenterals, they must be sterile.  In the process of proving that
>we can dconsistently deliver sterile drugs, we purposely seed an
>experemental lot of the drug product or a surrogte with bacteria.  We
>then use various methods of proving to the FDA that the bacteria are
>killed.  The FDA requires a SAL (sterility assurance level) of 10^6.
>What I want is a table I can reference so that I can use water as the
>carrier for the indicating organism, rather than the drug product. 

This is very difficult.  We argued with the FDA for far too long
eatting up money and killing sales of the product before we finally
just run the tests with the drug.  You can't show the FDA that water
is OK compared to your drug if there is any argument that could say
otherwise, . . .  No matter how many references you give the FDA can
always say, yes, but in your plant and specfic situation, the problem
to sterilize the drug is more difficult. 

You can run some tests without the drug but with everything else,  but
something must say why not adding the drug will not make a difference.

For instance:

We once showed that the drug itself was antimicrobial and
self-preserving -- so that was OK with the FDA.  

You also might want to ahve our ("my") book Preservative-Free and
Self-Preserving Cosmetics and Drugs editied by Kabara and Orth, (I
wrote chapter 3) ready as a reference  for FDA's  inspections.

>Having scientific studies to show the change in d-value with respect
>to these changes in solution  components, would aid in this.

-- Davin C. Enigl, Microbiologist.

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