Re: Expiration Dating
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|From:||firstname.lastname@example.org (by way of histonet)|
Sorry gang, Thanks for the correction Peter. I meant to say once a date
is established by stability testing for a product, that date does not
change from lot to lot. Stability is an ongoing process. Each lot is
monitored for stability. Example: If a stain has a one year shelf life.
That lot may checked at 3,6,9, and 12 months or monthly to guarantee
stability. If a product has two years expiry it may be checked a 6,12,18
and 24 months and so on and so on. They have to be within range of specs
that meets release criteria. Some manufacturers do use expirations dates
that are shorter than actual expiration as a safety zone.
Manufacturers can give you quite specific expiration dates under quite
specific conditions, however, conditions vary from facility to facility and
atmosphere to atmosphere and use to use.
Example: is a product has one year expiration and it is opened once at
room temperature and stored under the stated condition listed on the label
it should last to expiration dating. If that same product is used in the
field in extreme heat stability will be altered. This is why end-users
should establish their own SOP for products they use whether they are dated
or not dated. This documentation should be insurance from any type or
violation or recommendation regulatory inspectors would have.
Rande Kline HT (ASCP)
"Peter A. Takes" <email@example.com> on 11/02/98 06:13:54 PM
To: Barry Rittman <firstname.lastname@example.org>
Subject: Re: Expiration Dating
Yes and no. Expiration dates are indeed a consumer guide, but
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
diagnostic reagent bearing an expiration date, manufacturers must and
have the data to back it up. FDA will quite often look for such types of
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
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
expiry date. You may occasionally get longer life out of the antibody for
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
less than the actual product life, e.g., if there is a real life of 18
they put 15. This builds a little extra safety into the product's
True, companies cannot predict how individual labs will store the
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
aliquots once a week and then refreezing them. But, you should never see
expiration date without a storage conditions beside it. If stored under
conditions specified by the manufacturer, the expiry date should hold to be
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
> 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
> 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
> 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.
> 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
> degrees until needed and this extends the expiration date.
> At 02:25 PM 11/2/98 -0500, you wrote:
> >Yes, companies do real stability tests to validate shelf life. Shelf
> >may not always be tested from Iot to lot. The analysis or spec results
> >given a range during stability testing which determines consistent
> >stability. Expiration and certificates of analysis are usually
> >at time of manufacture. There are some manufacturers who establish
> >expiration from time of distribution. The standard is day of manufacture
> >which case, the certificate of analysis is also generated by the QC
> >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 <email@example.com> on 10/30/98 08:10:32 PM
> >To: firstname.lastname@example.org
> >cc: email@example.com
> >Subject: Re: Expiration Dating
> >Histonetters (including Vendors),
> >Can anyone describe just how an expiration date is established? I
> >these dates are, at best, just rough estimates. Do companies do real
> >stability studies to validate the shelf life of the product formulated
> >the identical manner as it is sold? Or, for instance, is there a
> >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
> >bulk batch is dispensed into a specific lot?
> >Inquiring minds want to know.
> >Ty Lee
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