Date: Wed, 12 Aug 2009 15:58:18 -0400
Reply-To: Roger Brauninger <Rbrauninger**At_Symbol_Here**A2LA.ORG>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Roger Brauninger <Rbrauninger**At_Symbol_Here**A2LA.ORG>
Organization: A2LA
Subject: Assigning expiration dates
I was wondering if there is a rule of thumb for assigning expiration dates
of working stocks, etc.  For example: An analytic method specifies that a
given standards solution (A) is good for one year (expires a one year after
preparation).  "A" is made from a commercially prepared standard, which has
its own expiration date.  In the situation where the expiration date on the
commercial material is one month after the current date and a solution of
"A" is made up from it, is the expiration date still one year after the date
of "A's'" preparation or much it be restricted to the expiration date of the
commercial standard. In this case one month.

To add to the discussion the Code of Federal Regulations, 40CFR, Section
58.113, (c ) states, "Where any of the components of the test or control
article carrier mixture has an expiration date, that date shall be clearly
shown on the container.  If more than one component has an expiration date,
the earliest date shall be shown." 

This is a difficult issue to come up with a unilateral approach because we
have seen instances where the exact same neat materials (Reference Materials
for example but it could be any chemical for that matter) which are sold by
different manufacturers have had different expiration dates assigned to
them.  So there is variability even with the neats.  The GLP approach is
certainly valid for a number of materials however, for example radioisotopes
but assigning an expiration date also depends on other properties of the
materials, for example whether they react or degrade (organics for example),
or do not (most metals).  Most producers say that it is appropriate to
re-qualify a material.   However it all boils down to having knowledge of
the materials at hand and the purpose for which they are used.


Roger M. Brauninger
BioSafety Program Manager

5301 Buckeystown Pike
Frederick, Maryland 20895
Direct line: (301) 644-3233      Fax: (301) 662-2974 
Email: Rbrauninger**At_Symbol_Here**    
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