I am learning to write a method transfer protocol.
I was wondering what would be the best criteria
to establish that the results from both the labs are about the same.
thanks
elango
elangom@yahoo.com

You both should agree upon some common strategy,
where you mutually can demonstrate, that an optimum is really the best solution. For example by changing pH. peaks move quite a lot, you can demonstrate, that at a certain pH all of the important peaks have the best equal band spacing.
You can calculate the changes in distances in Excel, or use the resolution maps of an optimisation software, such as DryLab from LCResources.

Imre makes a good point (and thanks for the plug!): the 'robustness' of the method is a big issue.

In more general terms, the criteria will depend on what you mean by "about the same". The strictest case occurs with an "regulatory" method (e.g., in pharmaceuticals). Under those conditions, your method will have to be validated. Robustness and lab-to-lab reproducibility will have been established as part of the validation process. The results from the new lab (to which you are transferring the method) should fall in the same statistical window you obtained during the validation.

(If you work in pharmaceuticals, sooner or later you will have to comply with ICH guidlines. If you haven't already done so, you can download them from: http://www.ich.org/ich5q.html#Analytical)

For the rest, "the devil is in the details". A lot of transfer problems arise from differences in basic lab manipulations that people assume are done the same way. Just as a quick example, I heard John Dolan give a talk in which he referred to the three ways of making up a simple HPLC mobile phase of 50% 25 mM phosphate buffer @ pH 2.7 / 50% MeOH:

1. the right way: mix 25 mM solutions of H3PO4 and KH2PO4 as necessary to get the pH to 2.7, then mix an equal volume of this buffer with MeOH

2. the easy way: make a 25 mM solution of KH2PO4 and adjust the pH to 2.7 using concentrated H3PO4, then mix an equal volume of this buffer with MeOH

3. the wrong way: mix equal volumes of 25 mM KH2PO4 and MeOH, then adjust the pH to 2.7 with H3PO4.

If the method is non-robust with respect to ionic strength, then you will get different results between 1 and 2. If the method is non-robust with respect to pH, then you will get different results between 1 and 3.

Based in what I've seen, the problem areas tend to be:
- pH
- temperature
- integration
- ionic strength
- column age/lot
- plumbing
in pretty much that order (I'm sure you'll get other opinions on this!).

-- Tom Jupille / LC Resources Inc.

Resp sir,
Can U provide me with the lastest changes made in validation of a method under ICH guidlines

ICH has changed the layout of their web site since my previous post in this thread (July 1999!).

Go to http://www.ich.org and follow the links there.