Re: Expiration Dating

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From:"Peter A. Takes" <> (by way of histonet)
To:histonet <>
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Yes and no.  Expiration dates are indeed a consumer guide, but
manufacturers, if
they do the stability testing properly, should be able to give you a VERY
accurate expiration date for their products.  As I mentioned earlier, if it
is a
diagnostic reagent bearing an expiration date, manufacturers must and better
have the data to back it up.  FDA will quite often look for such types of data
on inspection (and sometimes test the stability in their lab).  The minimum
number of product lots (and I stress MINIMUM) that should be used to verify and
validate this expiration period is three.  If manufacturers are smart, this
be an ongoing process and there will be in excess of three lots to support the
expiry date.  You may occasionally get longer life out of the antibody for any
of a number of reasons, not the least of which is that some manufacturers
(although perhaps only a few) may actually put an expiration date on that is
less than the actual product life, e.g., if there is a real life of 18 months,
they put 15.  This builds a little extra safety into the product's usefulness.

True, companies cannot predict how individual labs will store the
materials.  It
is not possible to control, for example, things like a customer storing the
product in a self-defrosting freezer that is unknowingly thawing your 0.005 ml
aliquots once a week and then refreezing them.  But, you should never see an
expiration date without a storage conditions beside it.  If stored under the
conditions specified by the manufacturer, the expiry date should hold to be
fairly accurate.

Peter A. Takes, Ph.D., RAC
Director, Clinical & Regulatory Affairs
Ph. 1-314-615-6964; Pager: 841-9351

Barry Rittman wrote:

> I feel that the discussion re expiration dates has been very useful but I
> should point out that expiration dates are generally a consumers guide only.
> While I believe that manufacturers are anxious to have the best quality
> control and to give some indications of a products useful life, there is no
> way that they can be expected to provide an accurate expiration date for
> many of their products. They can however usually often provide some
> guidance of the keeping qualities and reactivity under certain conditions
> and thus give a range. There are of course some exceptions. In general,
> however there is no way that they can control for the variable conditions
> of use and storage in different laboratories. I believe that someone
> suggested earlier to routinely test the product against known standards and
> I believe that this was very sound advice and should be carried out on a
> routine basis.
> As an aside I am still using some color film that theoretical expired in
> January 1990. The manufacturer estimates the approximate time of storage
> that this film is kept on the shelf at room temperature and assigns a
> realistic date for which the results can more or less be guaranteed. During
> this storage time the color properties of the film changes and the
> expiration date is a realistic estimate of the time beyond which color
> properties may change. I and many other individuals store film at minus 20
> degrees until needed and this extends the expiration date.
> Barry
> At 02:25 PM 11/2/98 -0500, you wrote:
> >Yes, companies do real stability tests to validate shelf life.  Shelf life
> >may not always be tested from Iot to lot.  The analysis or spec results are
> >given a range during stability testing which determines consistent
> >stability.   Expiration and certificates of analysis are usually generated
> >at time of manufacture.  There are some manufacturers who establish
> >expiration from time of distribution. The standard is day of manufacture at
> >which case, the certificate of analysis is also generated by the QC
> >department.
> >
> >There are various ways companies express lot numbers.  In certain cases,
> >such as monocolonal antibodies it would be best to contact each
> >manufacturer for their method.
> >
> >
> >
> >
> >
> >
> >
> >
> >tylee <> on 10/30/98 08:10:32 PM
> >
> >To:
> >cc:
> >Subject:  Re: Expiration Dating
> >
> >
> >
> >
> >Histonetters (including Vendors),
> >
> >Can anyone describe just how an expiration date is established? I suspect
> >these dates are, at best, just rough estimates. Do companies do real time
> >stability studies to validate the shelf life of the product formulated in
> >the identical manner as it is sold? Or, for instance, is there a standard
> >shelf life for IgG1s in a specific buffer at a certain concentration?
> >
> >What about multiple lots of antibody from the same batch of monoclonal?
> >When does the clock start ticking...when the mAb is generated, or when the
> >bulk batch is dispensed into a specific lot?
> >
> >Inquiring minds want to know.
> >
> >Ty Lee
> >
> >
> >
> >
> >
> >
> >
> >

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