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May 2011

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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:
Tue, 24 May 2011 08:27:51 -0700
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We used to determine the biological activity of each purchased raw material lot by the antibiotic assay method in the past, and compared it to the standard lot, which has been previously evaluated by some national standards lab. I just don't recall where we used to get the standard lot. Perhaps they are available through some of the vendors like VWR or Fiscger Scientific (in the US).
 
Kate Ambrus

--- On Fri, 5/20/11, [log in to unmask] <[log in to unmask]> wrote:


From: [log in to unmask] <[log in to unmask]>
Subject: Re: [PMFLIST] Converting I.U. to micrograms for Gentamicin Sulfate
To: [log in to unmask]
Date: Friday, May 20, 2011, 11:59 AM


I tried to develop an analytical method for this once.  As it turns out, this is a natural product with no less than five (if my memory serves correctly) related compounds/isomers present, in proportions which vary widely by lot.  Each of these related compounds has a different biological strength/activity, so the IUs (which is a biological measure) cannot be directly correlated to the gross active ingredient content (in mgs).

So the USP is simplifying, by requiring an analytical measure (without regard for biological activity), and the WHO is generalizing, by requiring a biological measure (irrespective of actual content).

Suffice it to say, the separation problem is significant enough that no one, to date (as far as I know), has been able to completely separate the compounds/isomers in quantities sufficient to test the biological activity of each one separately.

Good luck to you, though!

Cindy Duhigg




-----Original Message-----
From: Kate Ambrus <[log in to unmask]>
To: PMFLIST <[log in to unmask]>
Sent: Fri, May 20, 2011 1:05 pm
Subject: Re: [PMFLIST] Converting I.U. to micrograms for Gentamicin Sulfate


Do you no longer titrate the lot you purchase again a standard gentamycin powder 
urchased from a lab that sells these standards. That's what we used to do to 
stablish the activity of a purchased batch of antibiotic. I am assuming it is 
his "pure" substance referred to in the message below. I am sorry - we are 
oing back into the 90's here, and I no longer recall who manufactured these 
tandards in the US.

he biological activity does vary from batch to batch and there is 
o straightforward correlation between the units and the micrograms. It depends 
n how many units are in each unit of weight of your purchased batch.

ate Ambrus
--- On Wed, 5/18/11, LORRAINNE RIVERA <[log in to unmask]> wrote:

rom: LORRAINNE RIVERA <[log in to unmask]>
ubject: Re: [PMFLIST] Converting I.U. to micrograms for Gentamicin Sulfate
o: [log in to unmask]
ate: Wednesday, May 18, 2011, 5:02 AM

i Carolyn,
I suggest you go through the USP <81>  Antibiotics -Microbiological assay
Units and Reference Standards" it states that for the pure substance 1mcg
f biological activity is equivalent to mcg of weight.
With the Gentamycin Sulphate, definitely it is not a pure substance but
obody knows how much exactly is the Gentamycin and how much is the sulphate
n there. In that case you can use 1000IU/mg of Gentamycin as base.
Hope this helps
Lorrainne

n Mon, May 16, 2011 at 9:40 PM, BERES Carolyn <[log in to unmask]
wrote:
> Hello!

I'm looking for some information regarding conversion of International
Units per milligram to micrograms per milligram for Gentamicin Sulfate.

The Certificate of Analysis for drug powder I'm working with states the
potency in I.U./mg however the USP monograph (and nearly all documentation
I've found) states potency in micrograms/mg.  The only information I've
found that lists the potency for Gentamicin in I.U/mg is the WHO
Pharmacopoeia Library Monograph.

USP monograph: minimum potency = >590 micrograms/mg
WHO monograph: minimum potency = >590 International Units/mg

I'm interested in determining potency in micrograms/mg.  Since the minimum
requirements for potency appear to be the same (with the exception to
units), can I assume that I.U. is equivalent to micrograms?


Thank you in advance for your advice!


Cari


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he PMFList (http://microbiol.org/PMFList_info.htm) is operated from
he Microbiology Network (http://microbiol.org) and supported by
ur sponsors (http://microbiol.org/sponsor.htm) as a service to
he scientific community.
Please take a second to visit our sponsors' web sites and say thank you for 
heir 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
MicroBioLogics, Inc. - http://www.microbiologics.com
MODA Technology Partners: now a LONZA company http://lonza.com/moda
Pall - http://www.pall.com
NovaTek International - http://www.ntint.com
Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)
Veltek Associates, Inc - http://www.sterile.com
=================================
he nature of this service is to provide a medium for communication.  The 
pecific statements and endorsements of individuals participating in the 
iscussions are not necessarily those of The Microbiology Network, Inc., the 
MF, or the sponsors of the list.
------------------
he PMFList (http://microbiol.org/PMFList_info.htm) is operated from
he Microbiology Network (http://microbiol.org) and supported by
ur sponsors (http://microbiol.org/sponsor.htm) as a service to
he scientific community.
Please take a second to visit our sponsors' web sites and say thank you for 
heir 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
MicroBioLogics, Inc. - http://www.microbiologics.com
MODA Technology Partners: now a LONZA company http://lonza.com/moda
Pall - http://www.pall.com
NovaTek International - http://www.ntint.com
Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)
Veltek Associates, Inc - http://www.sterile.com
=================================
he nature of this service is to provide a medium for communication.  The 
pecific statements and endorsements of individuals participating in the 
iscussions are not necessarily those of The Microbiology Network, Inc., the 
MF, 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

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

MODA Technology Partners: now a LONZA company http://lonza.com/moda

Pall - http://www.pall.com

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

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

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

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

MODA Technology Partners: now a LONZA company http://lonza.com/moda

Pall - http://www.pall.com

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

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

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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