Ty:

Difficult to site published references, although there are likely many out
there, perhaps as far back as the '70s.  Most immunologists are aware of the
stabilities based on experience (information obtained over the long course of
education).  Unfortunately, I am in that category, not being able to site
specific references.  Try references like Trends Biotechnol 12(4):114-117,
1994; and J Immunol Meth 172(2):209-217, 1994; they may take you to more
specific references.

Sorry couldn't be of more help.

Peter

tylee wrote:

> Peter (or anyone else),
>
> Thank you for your response. Can you point me towards published references
> regarding the ..."generally known times that certain antibody isotypes are
> stable under specific storage conditions" ...that you mention below?
>
> ThankX,
>
> Ty Lee
> tylee@itis.com
>
> ----------
> From: Peter A. Takes <ptakes@stereotaxis.wustl.edu>
> To: tylee <tylee@itis.com>
> Cc: histonet@pathology.swmed.edu
> Subject: Re: Expiration Dating
> Date: Monday, November 02, 1998 9:52 AM
>
> Ty:
>
> Multi-faceted answer for multiple questions - What a manufacturer does
> depends
> on how they label the antibody.  If it is an In Vitro Diagnostic [IVD] or
> an
> Analyte Specific Reagent [ASR], and a company chooses to put an expiration
> date, FDA REQUIRES that this expiration date be backed by stability
> testing.
> This likely will be accelerated stability testing, perhaps to get the
> product
> on the market, followed by real-time stability testing.  The actual level
> of
> testing depends on the antibody and its application, but in most cases will
> be
> at least a protein concentration and a performance test, both to written
> specifications.
>
> In terms of lot-to-lot variation, it is required that there be process
> validation for the manufacture of the antibody (i.e., validation that each
> lot
> produced is identical to the one before it), and this usually is paralleled
> with stability testing.  Thus, by validating each lot is identical (i.e.,
> meets identical specs), you are essentially validating stability to be
> identical.  Companies will then put at least one lot/year into stability
> testing, or each lot if made less than once a year.
>
> There are generally known times that certain antibody isotypes are stable
> under specific storage conditions, but these are also dependent on the
> solution the reagent is in, concentration, etc.
>
> The clock starts ticking when the product is in its final form and has
> passed
> all the necessary quality control testing.
>
> Peter
> --
> Peter A. Takes, Ph.D., RAC
> Director, Clinical & Regulatory Affairs
> STEREOTAXIS, Inc.
> Ph. 1-314-615-6964; Pager: 841-9351
> ptakes@stereotaxis.wustl.edu
>
> tylee wrote:
>
> > 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
> > tylee@itis.com