Chromatography Forum

I’m leaving next week for Mongolia to help train lab personnel there to use HPLC (as part of a development grant). I’ve used HPLC for some time as an academic pharmacologist, but admit I’m not as up to date as I should be with QA issues. I could use some advise on a few things.

The lab I'm going to is "starting from scratch" relative to HPLC. They have however picked methods to analyze certain drugs that I believe have been validated, if not by a pharmacopoeia then by a drug company.

My question is:
-Should this lab perform a method (re)validation on each assay, even though it's been validated elsewhere, or will periodic equipment qualification along with QC samples and daily system suitability tests be adequate? If the revalidation needs to be performed, should it be complete or only address certain parts? If the latter, which would you suggest?

My second question is related to the inclusion of Quality Control Samples. In a document from the FDA it says:

[use] at least 3 known concentrations of analyte freshly spiked in control matrix, one being at a point 2 standard deviations above the LOQ, one in the middle of the range of the standard curve ("mid-range") and one at a point 2 standard deviations below the upper quantitative limit of the standard curve. [with] 6 replicates of each concentration.

I've used this approach for plasma samples.
a) Do you think these recommendations are appropriate for a lab testing drug formulations rather than plasma samples? If not, what would you suggest?
b) Should blanks always be included?
c) Can these same samples be used to determine accuracy, bias, and precision?

Many thanks for taking the time to help me,
Cory

Cory,

For Question 1 - You don't necessarily need to do a method revalidation when you visit your friends in Mongolia. However, you need to perform method transfers. Your company should have an SOP on transferring methods which should give you some direction. Usually a method transfer requires the originating lab and the receiving lab to each analyze a set of samples and then determine if the results are statistically not different from each other. In the transfer protocols that I ran, I usually had three sample lots analyzed in each lab on five separate days. That gives enough data to determine if the measured sample mean and assay variability from the two labs are not different. Your SOP may also allow for onsite training and analysis of control samples to be sufficient for a method transfer as long as the control sample results fall within a predetermined criteria. The most important thing is to have an approved protocol in place with predetermined criteria that will give you confidence that the receiving lab can reliably perform the procedures.

For Question 2 - I'm not sure where your definition for control samples came from exactly, but it is very different from the control samples that I am used to. Your quote sounds more like spike recovery samples for method validation. In my experience, a control sample is a sample from a specific product lot that has been stored in a controlled manner and is analyzed with every regular sample run. The results of the control samples are control charted over time to track method performance. If there is a sudden change in the control sample results, then you know that something has changed in the execution of the method. For example, a sharp jump in the control sample result might show that a new reference standard is out of spec. A gradual change might show the rise in temperature or humidity in a lab as the seasons change. If a control sample result is suddenly different, it might also trigger an investigation within the lab to make sure that the method was run correctly.

Have fun in Mongolia,

KarenJ