Validation parameters

Chromatography Forum: LC Archives: Validation parameters
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Saturday, June 5, 2004 - 09:31 am:

What parameters would you cover in the validation of an analytical method used only in assesment of clenliness of an manufacturing device?

I'm validating a filtration unit where we have to flush out a toxic filter preservetive before the system can be used. I got an analytical method from the supplier to detect this preservative. I couldn't get any method validation documentation from the supplier and I think I have to do some amount of validation/qualification for the method, myself. I was thinking atleast: specificity and LOQ. What about repeatability, linearity, accuracy, robustness and intermediate precision?

ICH divides analytical methods to three categories: identification, testing for impurities (quantitative/limit) and assays. In what category this would fall in?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Saturday, June 5, 2004 - 09:55 am:

What you are doing is essentially a limit test.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous #3 on Saturday, June 5, 2004 - 02:44 pm:

I have question for anonymous above (June 5th): As I understand it a 'limit test' is when you don't focus on quantifying something but, instead, just ascertain that it is below a certain level. What is the reason for taking this different approach in some cases. Why not just evaluate the result numerically against a spec., as would be done for most situations?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous#1 on Saturday, June 5, 2004 - 11:09 pm:

Thats exactly what I've been thinking as well. My reason would be that I don't need to do so much validation for a limit test. If you have a look at the table on ICH guideline Q2A on page 4:

http://www.emea.eu.int/pdfs/human/ich/038195en.pdf

you can see that quantitative impurity test needs full validation whereas limit test requires only specificity and detection limit?? What is the rationale, you can say you have a limit test??


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Tim on Tuesday, June 8, 2004 - 03:04 am:

A limit test is more of a qualitative test - is it there or isn't it. It gives an answer of > than a certain level or "None Detected".

A quantiative limit test gives you an actual quantity above the LOD/LOQ, or None Detected. Depending on the range over which you validate the method you may also need to set an upper limit for the method, so if you get a result above the range you have to report "Greater than X" because you can't acurately say that the value reported is a true value. This value must be well above the passing limit for you test.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Tuesday, June 8, 2004 - 10:44 am:

Another way of looking at this: a limit test is appropriate when the situation calls for "go / no go" (i.e., the only acceptable level is *zero*). An extreme example might be looking for product tampering (remember the "cyanide in the tylenol" case from a couple of decades ago? http://www.snopes.com/horrors/poison/tylenol.htm). You don't need to know *how much* is there, there shouldn't be *any*!

Cleaning validation falls in the same category.


-- Anonymous the second


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Lime on Wednesday, June 9, 2004 - 07:04 am:

You are trying to study assay for residual substance on a manufacturing device. Am i wrong ? If im not, its cleaning validation. and you need to :
- validate your method and determine LOD / LOQ
- study recovery (from the same material with the device ) in lab. conditions. For this, you may put your substance solution ( includes known concentration of subs.) on a measured part of a plate.Wait for a few hours ( depends how many hours it waits before cleaning in manufacturing area )Then swab the surface and analyse it. You will need this result to calculate real resudial value.
- After cleaning of the device you should get swab samples as you did before in lab.and you should repeat this process for three times.I mean after 3 cleaning, 3 sampling

actually there are 2 more sampling method for cleaning validation . You may do rinse sampling or placebo sampling as well.but swab seems more sensitive.

hope helps...


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