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